That One Level/First Person Shooter

Hope you've saved up enough ammunition...you're gonna need them for these particularly aggravating first-person shooter levels.

Bungie

 * In Halo 3, the level "Cortana" should have been subtitled "Master Chief's Happy Funtime Adventures In The Ninth Sub-Basement Of Hell." If there's anything worse than Flood rushes plus endless needle death spamming your shields from Flood turrets beyond easy range of your weapons plus the walls being full of Infection Form pods that will pop open at a single stray shot, and thus re-animate all the Flood you've already killed behind you...
 * Bungie apparently has not learned its lesson after the atrocity known as The Library in Halo, widely agreed upon as one of the worst FPS levels ever made. Hordes of zombies. Limited ammo. Repetitive level design. Constant death. Annoying ass robot that tells you to "Stop being human".
 * The real reason the level is hell:
 * Tsavo Highway Legendary, the part after the broken bridge where the two dropships followed by a Wraith attack you.
 * "The Oracle" on Legendary. There's the infamous Elevator of Doom infested with Demonic Spiders of the Flood type spawning from Mook Makers, and the level is also home to That One Boss, Mr. Heretic Leader. The elevator section makes the Library look easy.
 * "This Town Ain't Big Enough for Both of Us" in Halo 2's Metropolis. Two words: Sniper arena.
 * The courtyard sequence on Outskirts is much worse than the Sniper Alley, as the Jackal Snipers appear much further away and are thus harder to see, in random locations at random checkpoints.
 * The "Nothing but Jackal" sublevel of Delta Halo, which consists of a canyon followed by a waterfront area, infested with Drone swarms and Sniper Jackals, both of which are Demonic Spiders on Legendary, and little prospects for cover, particularly from the Drones, since they tend to flank you out of your cover.
 * Gravemind. This is not only the hardest Legendary level in H2, but the hardest on Heroic as well. Lack of checkpoints, lack of ammo for good weapons, long battles with large numbers of enemies at a time, lack of cover, frequent Melee a Trois events, culminating in the big Multi Mook Melee in the Mausoleum. At least it doesn't have the Flood, which High Charity adds in.
 * Speaking of High Charity... There's a reason Flood don't use sniper rifles in Halo 3.
 * in Halo: Reach, when playing on Legendary. The combination of a slow-turning gun that takes a full second to charge before firing and is  an open top isn't too bad on Normal, but combined with Legendary mode's easy-you-die-ness, it's positively infuriating. Be prepared to die at least a dozen times, and get used to hearing
 * It Gets Worse.
 * Tip of the Spear, HOLY CHRIST. Especially when you go to destroy that second Anti Air Turret; A pair of Hunters guard the door, and by this time it's INCREDIBLY likely that you're running low on ammo, and the only things the nearby grunts have are Needlers and Plasma Pistols. That's right, you're very likely to have to kill Hunters using small arms weapons. God help you if you wasted the plasma launcher from earlier.
 * Good God, "Exodus". There are Brutes and Jackals with Needle and Concussion Rifles, as well as at least one Fuel Rod Gun, sitting behind cover in a labyrinthine building. And then there are several ghosts just running around, waiting to kill you. Even if you take the rocket launcher, good luck hitting them.
 * The Marathon trilogy features a few. Most are in the first game, as the level designers gained experience...
 * G4 Sunbathing is one of the few vacuum levels in the series, where your oxygen is constantly draining and only two of your guns work. This level was long considered the only "un-viddable" level, i.e., unbeaten when starting with just the pistol.
 * By far the most widely loathed level is Colony Ship For Sale, Cheap!, infamous for a "puzzle" in which several platforms must be raised and lowered by switches into an approximately stairway-like configurations. The problem is that each switch is in a different room far away from each other, and the platforms are a ways away from each other, making it difficult to judge whether they're at the correct height. Oh, and Marathon has no jump key, so you either get the platforms exactly right or you grenade jump.
 * The level designer also created the final level for Marathon 2, which he calls an "apology" for Colony Ship For Sale, Cheap!
 * The fan remake alters the puzzle so the platforms automatically go to the correct position, and Unfortunately, the puzzle was restored in the latest Aleph One version in the name of game accuracy and classic authenticity.
 * Neither High Nor Low is one of the worst examples in video game history, due to the crippling lack of save points, the complete lack of recharge stations, and the traps from hell. If you start this level with a full shield (preferably a double shield), you might have a chance.
 * There is a hidden shield recharger at one point in that level. Worse is Pfhoraphobia, which has neither shield rechargers nor pattern buffers.
 * Ingue Ferroque, the final level of the original game. Three circular corridors with hordes of Troopers, little ammo, and if you run out of grenades or fusion batteries, the level is Unwinnable, as you have to shoot several switches to proceed.
 * Marathon Infinity features two vacuum levels in a row, Acme Station and Post Naval Trauma, with few opportunities to recharge your Oxygen. Acme station is generally regarded as the hardest level in the entire series. Only eleven people have ever completed the Vidmaster's Challenge for that level. (Note that these films will only work on the original Macintosh version of the game).
 * If you're used to low difficulty, the rate at which you use Oxygen on the highest difficulty level is shocking, to say the least.
 * There are also a number of "dream" levels and secret levels which connect you to alternate timelines. If you make a wrong turn, you'll end up on an earlier level, and Acme Station is one of the possible destinations. One of the secret levels is Carrol Street Station, a vacuum version of the final level in the game, with a wrong turn that will connect you to Acme Station for three back-to-back vacuum levels. Ooh.

Rare/Free Radical

 * Level Eleven: Teamwork in Second Sight, thanks to being an Escort Mission with numerous escortees and a big, confusing map. Apparently "Teamwork" means "Vattic, run around healing everyone while they obliviously stand in front of these enemies and get shot constantly."
 * There are several such levels in GoldenEye, Aztec probably being the most notable.
 * Aztec, the first bonus level and penultimate one of the entire game. Tellingly, it's actually harder than the final level of the game, whose only real difficulty is figuring out the safe path in the Golden Gun room. Even the official Player's Guide says this is a Luck-Based Mission. Aztec is hard even on the easiest difficulty, but set the difficulty to 00 Agent, and let's count the ways:
 * The very start is a deathtrap with three guards with grenades and assault rifles against you with a pistol. If one throws a grenade, it's a question of whether you decide to hit restart or just die. Your survival is entirely based on what they decide to do.
 * The level is a hive of respawn points for enemies with either high-damage assault rifles or even higher damage hitscan lasers with crippling knockback. You will succeed or fail based on where they are spawned, not on the basis of anything you might do.
 * The vent screens, which you cannot see through but your enemies can, making it very hard to next to impossible to get through the level with the health that you need to survive the final part of the level mentioned below.
 * There are multiple drone guns (six in all) which you must destroy without being sighted by them, sometimes by firing blindly. If you get hit, they will do massive damage.
 * The centerpiece of the level is a gargantuan fuck you trap, with the shuttle bay doors closing and forcing you to open them in order to complete the mission. Climbing the ladder up to them borders on impossible, and beating the mission can only be done by closing the doors yourself because the final script switches state without checking if they're open or closed. Yes, you basically can only win by exploiting a programming oversight.
 * There's more. Part of the mission involves reprogramming the shuttle. To do this, you must do battle with Jaws, who totes double assault rifles (but whom you can kill by getting so close that he can't use them against you). This is while the infinite guards come to kill you (fortunately, the guards are finite until you kill Jaws). You must then retreat to the control room, and then fight your way back to the central room, so that you can launch the shuttle, where the above ladder comes into play.
 * Surface 2, considering you can't see a thing, it's not obvious where the mission-failing cameras are pointing or what they can see, the objectives are very far from each other, and it constantly spawns enemies homing in on you. And your primary weapon is the Klobb.
 * Control. You have to protect Natalya as she tries to reprogram the guidance system of the titular EMP weapon so it does a reentry into Earth's atmosphere instead of KOing London's electrical security systems (thus allowing Trevelyan to steal all the money from the London bank unhindered). This involves trying to keep her alive while hordes of enemies come and try to shoot her, and she just stands there where she can easily be shot (which to be fair, you kinda have to do in order to reprogram the damned thing). She dies in only two or three hits, and to make things worse, the desks and computers near the console Natalya's working on, like everything else in the game, are Made of Explodium, and are close enough to kill her if they're destroyed during the shootout. Of course, you fail the mission if she dies.
 * Facility - but only in the case of unlocking it for the awesome Invincibility cheat. What makes it so bad? Well, you have a ridiculously short time (2:05) to complete the mission, forcing you to do it in a way that requires you to take damage constantly and leave most guards alive to fire at you for the remainder of the mission. Then there's the luck-based aspects: whether a guard will have an on day and get a headshot; the spawn location of a required NPC; the actions of another NPC (Alec can and will get stuck in the containers you're required to blow up); random guard actions can mess up the run badly (such as a kneeling guard when you're quickly aiming that headshot - while running), and so on. Even the best players have trouble beating the level to get the cheat.
 * The Archives cheat is almost as bad, since it gives you a paltry amount of time to get it. Even strafe-running through the level and not stopping to fight anyone, it's rare to beat it with more than a couple of seconds left on the clock.
 * Train is pretty damned hard on 00 Agent, since you begin the level armed with a pistol and have to engage in a shootout in a cramped boxcar with only (explosive) crates for cover. Getting through most of the level is pretty easy with the careful use of cover, but it becomes much more difficult near the end when guards wielding dual ZMGs appear - and then you have a goddamn hostage situation which leaves you with about 4 seconds to escape. Even for experienced players, it can easily go wrong.
 * Caverns on 00 Agent is pretty hard for a number of reasons: it's incredibly long (easily 20-30 minutes), all the guards have excellent weapons (and many have armour), there are three drone guns you have to destroy, you can't kill any of the scientists by mistake, and then at the end waves of troops wielding RC-P90s appear to kill your ass if you're not fast enough. Getting to the final hallway and dying there after all that work just makes it so much better.
 * Perfect Dark has Maian SOS, which in 00 Agent is the worst level ever programmed for the GoldenEye engine. Why?
 * It's a level you've already played three times, and it really wasn't that interesting in the first place.
 * You're Elvis, which means you have to aim much higher than you're used to in order to get headshots.
 * It's grotesquely unforgiving. You start with half health. There is no way to get more health. Everyone is armed with fully automatic hitscan weapons that can kill you with a handful of shots. At any point in a mission that can easily take fifteen to twenty minutes a try, you can be killed by a single enemy before you even realise they're there.
 * There's a guy with two instakill weapons. You need to hit him with the Psychosis Gun and then follow him closely so that he won't despawn, because you have to pick up his weapons when he dies.
 * Didn't pick up his weapons? Oh dear, you'll almost certainly run out of ammo trying to chew through the Maian saucer's unholy number of hitpoints.
 * And after all that, you're rewarded with the sight of Elvis being shot ONCE with a tranquilizer, which should be a minor inconvenience at most, and keeling over unconscious. And the Psychosis Gun, a deeply useless gimmick weapon on any level other than Maian SOS, since the other levels don't tend to have a single enemy with vastly more offensive power than all the others.
 * Don't forget the second hardest mission in the game, Carrington Institute: Defense, which has not only enemies that have shields but also armed with K7 Avengers that could kill you (or at least significantly lower your health) in one burst. Then at the end, you have to send a bomb-ship flying out of the Institute before it destroys the place by using the Decoder on it, which is pretty tedious considering you have to stand there not fighting the infinitely respawning enemies for about 5-10 seconds.
 * In general, almost every level becomes That One Level when you're doing speedruns to unlock the cheats, especially since sometimes the limit is so strict that you have to do objectives in a certain order. Other times, you have to do parts of objectives in order!
 * Area 51: Rescue has you grabbing a disguise to help you complete one objective, but doing something else entirely before actually going to the area for which you need the disguise. And a time limit appears as soon as you grab the disguise, so going to waste your time doing anything else is a Violation of Common Sense.
 * Another instance is actually an exploit of a Good Bad Bug, and is thus is a huge Guide Dang It. Who else would think to send the CamSpy to trigger a cutscene while the safe-cracking sets off the alarm that would otherwise call the meeting in the cutscene off?
 * Chicago: Stealth is not an overly complicated level, but it does leave you with very little time on 00 Agent to place the tracer bug on the taxi before it flies away. Messing up this single objective fails the entire mission.
 * Other fun candidates for worst level in Perfect Dark include:
 * Air Force One: Counter-terrorism. You begin the level running around punching armed guards out instead of shooting them like a sensible person. Next you have to run halfway across the level to get to the President, whom you have to protect from waves of shielded troops carrying assault rifles. (Yep, it's another damn Escort Mission). After you've rescued him, you've still got to run all over the place completing another couple of objectives before it ends, and you can easily be shot once and die at any time.
 * Deep Sea: Nullify Threat. Let's see, it's pitch black for most of the level, and you have to fight your way through a bunch of cloaked guards running all over the place while you have only a shotgun. Next you have to protect Elvis while you two disable the Cetan weapon. After that, you have to fight off endless waves of little Skedar, Mr. Blondes and still more of those damned red-uniformed guards before the ending sequence, which gives you one minute to escape the ship before it explodes.
 * Attack Ship: Covert Assault on Perfect Agent. You begin the level facing two Skedar with Maulers. With a knife. Run out of ammo for the Mauler? Great, now you don't have that or your knife either. Back to Good Old Fisticuffs - oh wait, they're incredibly strong aliens who can kill you in one or two swipes. Now if you're somehow still alive after all that, you have to fight your way through the ship battling about, oh, let's say two dozen more of them until you get to the end and capture the bridge - after fighting off a Zerg Rush of another half dozen of them.
 * Perfect Dark Zero has some pretty tough levels too, the worst one being the Temple level, the difficulty ramps up when you have to cross a long bridge full of enemies, by the time you get through it, you probably won't have much health left. The worst is yet to come however, next you have Demonic Spiders in the form of elite female guards who can turn invisible and carry plasma rifles which will most likely kill you in 2-3 hits, and if you die there, you have to start over form the bridge again, even on Agent mode this is tough, but it's completely fucking insane on Dark Agent.
 * While several levels in the original Time Splitters could be ridiculously hard, special mention goes to 'Mansion'. Two-thirds of the enemies carry shotguns which can kill you from halfway across the house in one shot in Hard Mode, as well as the fact that enemies can literally appear out of thin air, and there are no checkpoints. Seeing as the timed secret can be unlocked in at least ELEVEN minutes, the people at Free Radical were aware of what they had created.
 * Most of Time Splitters 2 is straightforward arcade-style action, and that's part of the reason why the NeoTokyo level is so universally loathed. The first half of the stage involves following a baddie back to her gang's hideout without her or any of the numerous security cameras noticing you. It doesn't help that she strolls along at a snail's pace, and that getting noticed for even a second means starting the whole damn level over again.
 * You want a level that is really hard in that game? Try "Atom Smasher" on Normal or Hard. Playing this level on any of those difficulties is equal to playing "Mansion" in Time Splitters but almost worse. There are snipers everywhere, hardly any health or armor, henchmen wielding Soviet S47s and silenced pistols that can chew through your armor (if you have any), checkpoints that are few and far between, sentry guns with cameras (on one occasion you have to destroy one up close), and short detonation times means you'll be bald after completing the level after so many damn times. The BGM for this level means "You are screwed."
 * Time Splitters: Future Perfect has the "The Hooded Man" level. In the last part, you must protect from 'Splitters till he gets inside a base. This is during the middle of a firefight. You have the high ground to rain death on them. Sound easy? They cloak on and off predator-style and zig zag. When they get close to, they do high damage jumping slashes. You'll notice one coming and mow him down, only to then see 2 tearing  a new asshole. On hard difficulty, this part is infuriating.
 * Not to mention that as well as the enemies being cloaked for a lot of the time, they're a similar colour to the environment anyway, and on the last part of the level they're very far away even with the sniper scope zoomed in.
 * Future Perfect also has a level called 'Robot Wars'. Your enemies are the robots. Those robots have plasma autorifles, rocket launchers, and a ridiculous amount of health. You have a laser handgun that does little damage. If you don't want to waste ammo, you'll have to aim for the robot's 'heads'. The problem is, it's hard to tell if you're actually hitting them in the head, and they'll be firing rockets at you. Finally, constantly hearing "We are legion", "Surrender or be destroyed", and "Robots are superior" will annoy the hell out of any player unfortunate enough to play through this level on 'medium' difficulty. Let's not talk about Hard.

Crytek

 * The final level of Far Cry, most notably the penultimate fight in the volcano's rim. Locked into a wide open area with hordes of rocket-spamming mutants, ninja snipers that can shoot you from beyond the draw distance, and a lone healthkit, on the far, far side of the arena. How do you win? By cheating and piling crap on the airlock door, so it won't lock behind you. Even then, you get sniped to death 9 times out of 10. And after that? If the designers didn't prove they hate you yet, as you round a corner, you get insta-killed by hidden guards with rocket launchers.
 * The second level, on the derelict carrier, can be a nasty wake up call level. At the end, you have to fight a helicopter and several mooks on the flight deck of the carrier. For a new player, it can be problematic.
 * The sections of Crysis which places the player in a tank and a VTOL transport are generally considered greatly inferior to the rest of the single-player game. The tank cannot be repaired or rearmed, so must be abandoned when it has taken too much damage, and the VTOL is fairly difficult to maneuver accurately. This wouldn't be so bad if it weren't for the fact that you are forced to engage alien flyers in combat, something which is quite frustrating.
 * The tank mission is nothing compared to the first alien ship mission with instakill aliens who are hard to aim at, and no gravity, and no map makes getting lost easy.
 * THAT level was really a pain in the ass.

ID Software

 * Seawall Battery from Wolfenstein: Enemy Territory was a level in which the Allied team must stage an uphill assault along two possible fronts, infiltrate the Axis bunker, and plant dynamite at the final objective in order to win the map. The problem? One front was a virtual murder hole in which the Axis team could toss airstrikes down onto the beach and murder the entire Allied team, while one forward and exposed MG nest could blanket half the beach, while a lower altitude, and partially occluded nest provided cover from blind spot grenades. The other front featured a back door as an only entrance that could only be accessed should the Allied covert operative posses a uniform that would allow him to open the door. The problem? The passage to the back door featured an up hill climb into a funnel-like valley that was probably the worst choke point in the entire game, beneath which, land mines could be planted. If the Allied team managed to prevent Axis from constructing their forward spawn post (which professional teams would ignore in fear of providing the Allied team with a uniform for the back door) they were faced with an MG nest, and the pleasant opportunity to camp the back door in hopes of access to the final objective. Should an engineer sneak in alone or with the help of a covert ops, the player still had to manage to make it to the bomb site, plant the bomb, and defend it for 30 seconds while much of the enemy team hunted them down and disarmed it. A broken level, but one of the most rewarding to play on offense.
 * While the level does clearly favor Axis, the Allied team does have one advantage. The final objective is far from Axis spawns and other populated areas, meaning if you manage to somehow sneak in and plant the dynamite, chances are you'll win unless some sneaky Engineer guards the objective.
 * Episode four of The Ultimate Doom - entitled Thy Flesh Consumed - was produced a year after the original release of the game, and was much harder. In fact it began with the two hardest levels in the original stock Doom, more difficult even than the episode-ending boss battles. E4M2: Perfect Hatred trapped the player in a small underground cavern packed with monsters, with most of the accessible area suspended above a damaging lava floor and the previous level, E4M1: Hell Beneath, was no slouch either, with only token quantities of health and ammmo. The player would frequently have to begin E 4 M 2 half-dead and out of bullets (before quickly become fully dead courtesy of the Doom equivalent of a Zerg Rush).
 * Final Doom, Plutonia Experiment: the secret level 32 "Go 2 It." For those who can't tell from the rather frantic pace of the video (finding a non-speedrun of the level is nigh impossible), it's packed to the gills with Cyberdemons, which if you recall are end-mission bosses by themselves that haven't really LOST any power since then. If that wasn't enough, you also have more ArchViles than there are weirdos at an anime convention, all individually capable of both heaping on the damage on their own and resurrecting everything in the level that isn't an Arch-Vile, Cyberdemon, or Spider Mastermind. And, like many WADs did in the Doom days, their numbers double if you're playing co-op. If you're intending to actually clear a path through the monsters in order to survive, as opposed to having Jedi-like reflexes, expect to clear the level (if you can) with a kill rate of somewhere around 1000%. Yes, one thousand. Meaning you would have killed each individual enemy ten times over.
 * A lot of the Nintendo Hard megawads have plenty of very hard levels with high monster counts, but some of those levels stand head and shoulders over the rest.
 * Map24 of Hell Revealed, Post Mortem, the hardest map in the entire megawad, not only has 579 enemies at the highest difficulty settings, but there is also virtually no cover without improvising.
 * A Post Mortem-style map, Hard Target of the Kama Sutra megawad. This one has over 1,700 monsters in the map along with the aforementioned lack of cover. Have fun beating that.
 * Hell Revealed 2's Map 32 has over 1,600 monsters, a lot of them being of the heavyweight variety. Good luck beating this one without reloading.
 * The recently-released Speed of Doom's Map28 and final level, having over 2,800 monsters and exactly 2,010 monsters each, respectively... Those two levels alone make the first Deus Vult look easy.
 * Plutonia 2's Go 4 It. Not nearly as tough as the rest of the levels on this list, but it's certainly a fitting successor to Go 2 It.
 * Return to Castle Wolfenstein has two stealth levels. The first is an infiltration mission, where you have to sneak into a Nazi base by following a supply truck to a compound in the middle of a forest. This takes place after you mow down enemies in the few levels preceding this level. Now here is the hard part. You have to ensure no alarms are set off in order to infiltrate the base, which can be done by smashing them. The fun part? It's rather easy to get detected while stalking the supply truck because there are sniper towers strewn throughout, as well as guards patrolling about. The same thing can also happen once you get into the compound, because there is a chance a Nazi guard may be around, and there is a sniper post inside the compound. The next stealth level is an assassination mission. You're pitted into a village, and your objective is to kill off five important Nazi officers inside the village. The same conditions as the previous stealth level apply to this one: Ensure that no alarms are set off. The hard part? It's easier to get detected in the village than in the forest, and there are always going to be at least a guard or more walking about. Heck, there can also be a few guards patrolling around certain areas of the village, and the paths in the village are linear.
 * Wolfenstein 3d has E6m1. Imagine a level made up mostly of long hallways, with perpendicular niches. Now imagine that nearly all of those niches contain an "Officer" who will likely step out and block your path (likely shooting you for Massive Damage if you are reckless) unless you take a perfectly straight line through the halls, dead-center and just run for it. Have fun beating it if you're into hundred percent completion. Not a super-hard level but just so uninspired. Also, the music may drive you nuts; See and hear for yourself.
 * That level is nothing compared to the labyrinthine hell that is E6M7. Then again, the entirety of Episode 2 could also count because of those fucking mutants.
 * Levels 16 and 18 of Spear of Destiny put anything in the original game to shame. The Game Mod Spear Resurrection ups the ante even further with its level 13, The Great Escape, which would have already been an extremely long and difficult level but gives you the additional problem of not having weapons in the early part of the map.
 * Quake III Arena (and by extension, Quake Live) have space stages like The Longest Yard and Space Chamber. You will lose a point if you fall off or are knocked off the stage by another player.
 * There is also Apocalypse Void. It's a space level made up of a bunch of floating platforms that move up and down. It's extremely easy for a railgunner to knock you into the void while you're in airborne (as when using jump pads), plus there is nowhere to hide.
 * In the original Quake, Hell's Atrium, The Pain Maze and Azure Agony are all extremely difficult (the last three before the final boss). All have dozens of enemies, numerous environmental traps and limited ammo. The last hidden level, The Nameless City is even worse.

Valve

 * Half Life has one: Xen. The whole crux of it. You just went through going through Black Mesa, fighting for your life against an alien invasion and a military clean up battalion. What are you treated with? Platformer hell.
 * The Blast Pit level in Black Mesa. Repetitive design, unintuitive puzzles, and a near-total dearth of supplies just makes it a completely unenjoyable level between two excellent ones.
 * The first half of Sandtraps, where hordes of Antlions spawn at you if you walk on the sand. Of course, the game immediately makes up for it by letting you control the Antlions in an attack on a Combine fortress.
 * There is now an achievement if you manage to go through the entire level without touching the sand.
 * Breaking into Nova Prospekt on harder levels. Not one, but two gunships will fire upon you, along with a squad of guards. Health is rare, and the only steady supply of rockets (the only weapon actually useful against gunships) is out in the open, forcing you to take a few hits in order to resupply. While you can distract the gunships with your antlions, they have a tendency to come back to you, bringing the gunships' fire with them.
 * Nova Prospekt's defence level. Oh lord. Playing fairly is damn hard. As such, most players use "alternate" strategies involving bringing more turrets or just plain hiding.
 * Many players have an extreme dislike for Half-Life 2: Episode One's elevator part. It's not as hard now because the developers patched it to be easier.
 * Defending White Forest from the striders in Half-Life 2: Episode 2 should be party central. You get a new, unique weapon that blows this once-formidable enemy into fun-sized candy bars, plentiful supplies, and even radar to tell you where you're needed. The hunters, however, make this level tougher than getting your ass beat in front of the girl you like. Each strider comes with 1-3 hunters (which fire on you constantly), and if even one of them is within firing range when you take out your fun new bomb it dissolves into spare parts. You can kill them in one hit by running them over, but they can sidestep it somewhat easily. As such, White Forest has the distinction of being Best Level Ever for half the people who play it and That One Level for the other half.
 * Ravenholm can suffer from being That One Level - not so much from difficulty, however, as the fact that you need to take a break every ten minutes so recover from the constant waves of headcrabs that leave you a gibbering wreck.
 * Valve's multiplayer games are not immune to this. Team Fortress 2 has 2fort, which is infamous for having long, boring corridors, an unintuitive map design with unfortunately-located chokepoints, an average of four snipers per server (maybe one of which is aiming for something that isn't another sniper), an average of five engineers per server (maybe two of which have achieved more than five sentry kills), and it taking herculean efforts to capture the flag (mostly due to the engineers in the flag room or outside the upper respawn). This problem is exacerbated by playing on large servers or with instant respawns (both are popular options among TF2 players). It does have a large fandom in TFC veterans and people who are new, though. But then, Capture the Flag maps (with the exception of Turbine) in general are disliked due to their stalemate-heavy matches.
 * This is largely caused by the fact that 2fort is essentially a string of ports, with little design changes in its port to Team Fortress 2 (unlike, say, Well).
 * Nobody seems to like Hydro, partially because of the confusing dynamic map layout, partially because you're either stalemated or getting steamrolled.
 * The first Payload Race map, Pipeline, is developing a bad reputation for--you guessed it--being too easy to stalemate on. The worst part? The stalemates occur on the first two map "sections," which AREN'T the sections that you have to win to win the round! Winning one of the first two sections just gives your team a bonus head-start in the second or third section. It's not even a large head-start, and if the teams each win one section then nobody gets a bonus. The WORST worst part? There's no timer, meaning matches could go on indefinitely until the team composition changes as people quit and join.
 * Left 4 Dead 2. The Barns. Oh good, you've made it all the way to the stadium! Now all that's left is to open the gates and walk fifty meters to the safe room! Enjoy swimming upstream in an endless flood of zombies, with the occasional special infected throwing random stuff at you for shit and giggles!
 * And let's not forget the Tank that has a tendency to spawn inside the Safe Room at the end of this insanity. Who doesn't love trudging through a massive zombie orgy with no hope in sight from the get-go and losing all your teammates in the process, just to open the door that leads to the one room in each level that's guaranteed sanctuary... and come face-to-face with the closest thing this game has to a boss blocking the doorway?
 * Though The Barns throws a tsunami of infected at you near the end, The Mall can be hell all the way through because of the game's tendency, despite the Director's quasi-randomization, to make the Mall level a special infected orgy; it's unlikely you'll get through the Mall without being assailed by a near-constant stream of Special infected. Not to mention it's one of the longer stages in the game, and the Horde-summoning event is rather ruthless.
 * Hard Rain. Especially the second half. Because there's nothing quite like wandering around in a sugar mill filled with witches and a flooded town filled with zombies while rain cuts your vision down to ten yards every five minutes.
 * Sugar Mill, Witches wandering through the entire level like a swarm of angry bees assisted by infected and god forbid a tank, the kicker of this level is that there is an achievement where you can't kill any of the witches. Have fun surviving on expert.
 * For those who don't know, Witches are game changers, they make you go through a "Shoot everything that breaths, and then some" to a state of "super stealth mode" F.Y.I., the level is as stealth unfriendly as it gets.
 * It doesn't help that the bots don't know the meaning of stealth. More often then not you'll have a bot (or a stupid teammate) disturb a witch. However running through the level without disturbing any of them can be done, but its just so bloody hard you can't predict the outcome.
 * To further elaborate on Hard Rain, the second half of the campaign takes place in a storm so fierce that it often reduces your visibility to nothing farther than what's right in front of your face, and blots out much telltale sounds that could have saved your ass to hear ahead of time. But the real nasty part is the beginning of level 3 of the campaign, Mill Escape: to begin, you have to maneuver back through the sugar cane field you just went through, except this time, the storm comes and washes away whatever visibility and strategy you did have planned. In a series based around knowing your environment, sticking together and being cautious and aware, this segment borders on Fake Difficulty.
 * And god help you if you actually play Hard Rain in Realism mode; no glows, teammates don't respawn in closets if they died, Witches kill you in a single strike, and common infected have more resistance unless you shoot their head. Combine Realism's rules with the hurricane effects and the huge amount of Witches in the sugar mill, you will have the ultimate hard maps in the entire series. Pray that your teammates are smart enough to hunker down and stay close to you when the storm kicks up. And to top this all off, Realism or not, when the storm intensifies, your voice on the microphone gets muffled due to the high winds and thunder, making communication very difficult unless everyone goes into a building or waits for the storm effects to stop.
 * No love for the bloody roller coaster? You have to set a roller coaster running and go along the tracks while being endlessly swarmed by zombies for the entire trip. And God help you if you fall off, because in most cases you then have to go right back to the start to get back on. There's also a bit on a building site where you have to run a zig-zagging queue-rail type gauntlet with lots of insurmountable chicken-wire fence to get to the button to turn the alarm off (that's right, a switch-the-alarm-off button, which doesn't even stop the horde, not a safe-room). Wait, did I say insurmountable? I meant insurmountable to you. Zombies can surmount it without any trouble whatsoever. And there are millions of them, and they infinitely respawn. Thanks, Director. Have fun.
 * The endgame of The Parish. A long, long run across a bridge from Hell, with never-ending waves of zombies, a Tank that has plenty of cars to throw at you, and just when you can see the helicopter and the Director starts throwing more waves of zombies at you... you learn you have to navigate a somewhat-confusing path of concrete barriers. Especially painful in that if you're playing with CPU teammates, a) they can't carry pipe bombs or Molotovs that will distract or block the majority of the Horde that's headed your way and b) they tend to like to patch themselves up without realizing there's a Tank right behind them! Ugh.
 * The Parish also has an impound car lot in the 3rd map that is filled with cars with activated alarms. Naturally, your aim has to be spot on if you plan to shoot any infected or risk hitting a car. If you wind up triggering a car alarm here, it is likely during the fight, your bullets will hit another car and summon another horde after the one before it and it can get a lot worse if your teammates are trigger happy, bad shots, or panic easily (luckily survivor AI can't trigger alarms at all). This can lead to a huge chain reaction of several hordes bearing down on you. Smokers can yank you to an alarmed car (especially on the bridge above you where you can't see them), Jockeys can ride you into a car, and Chargers can ram you into a car. If a Tank shows up? Better hope you can dodge flying cars!
 * For some players, Swamp Fever as a whole is That One Level - not because of the difficulty, but because of the grungy, homogenous environment (an endless stream of puke-green as opposed to the colourful other campaigns) and the abundance of watery regions slowing down movement. But then there's the last part of Plantation, simply because the Director has the choice of throwing two tanks at you. At once. On as low as Normal. Not fun.
 * The Passing finale in Left 4 Dead 2 is also a total bitch to tackle. The Left 4 Dead 1 survivors cover you in the main intersection but once you start heading to the back street and back alleys, they won't be able to see you so they can't help and that's where all the trouble starts. The gas cans are spread so far apart from each other that every trip is a big risk for being pounced and just like in Swamp Fever's finale, there will also be two Tanks to fight after the first Tank.
 * The Sacrifice finale in Left 4 Dead 1 is a total pain, mainly in the actual sacrificing part. As 3 Tanks rush in to kill everyone, someone has to jump off the bridge and restart the generator. 9 times out of 10, a Smoker will yank the would be hero and is usually in a place where bots can't see the Smoker, leaving the player to die. Oh and did I forget to say that not only bots will never sacrifice themselves, but if three survivors are killed (or all incapacitated on the bridge), it counts as a Nonstandard Game Over for the last survivor alive? The same finale in Left 4 Dead 2 is significantly easier due to the addition of melee weapons, bile bombs, and more special infected types, meaning Smokers won't always be there to stop you.
 * The Voltigore tunnels in Opposing Force. It's a series of (wait for it...) sewer tunnels filled with Voltigores. The tunnels are pitch black, requiring you to use night vision, which only shows about ten feet in front of you; naturally, there's voltigores that will shoot at you from beyond the range of your night vision. Said voltigores can take disproportionate amounts of ammo to kill, have devastating electrical attacks, and self-destruct upon death. As you can probably guess, there's almost no ammo or health in the tunnels. Snarks will do quite a bit of damage to them, but snarks are exceedingly rare in Opposing Force. Thankfully, there's an easy AI Breaker once you get to the second set of tunnels; the voltigores aren't programmed to leave the tunnel, so you can just take out the Shock Roach and cherry tap them to death while dodging their attacks. It's better than wasting your ammo, because immediately upon leaving you're hit with a horde of Shock Troopers, backed up by a few more goddamned voltigores.

Star Wars

 * Star Wars: Dark Forces Saga had Anoat City (the third mission). It's basically going through a maze of sewers, and it's a real sewer, with real sewage. So if that thought alone doesn't make you want to leave, well there's those dang Dianogas (the trash compactor creature from A New Hope), it's dark, and well, did I mention it was a maze?
 * Jedi Knight 2: Jedi Outcast has Nar Shaddaa, all of it. The previous mission, you just got back your lightsaber and force powers. So, does the game provide you with plenty of stormtroopers to cut loose on? Nope! Instead, you get a non-stop diet of snipers and grenade-throwers!
 * For clarification, the sniper rifle is the one non-explosive weapon in the game that you can't block with the lightsaber. The only way to avoid damage from them is taking cover (which is suddenly nonexistent once you're actually in their territory) or hoping that both you have a full Force bar and they only fire one beam at a time when they shoot you (Kyle will auto-dodge using Force Speed if both conditions are met. Sometimes.).
 * It's not really that bad unless you encounter a certain bug that makes the third level impossible to complete.
 * If you want sheer unadulterated hell, you want Outcast before you get your lightsaber. These stormtroopers aren't The Goomba like in most Star Wars games - they are unstoppable gods of destruction. They're smart, they sneak up on you, two will go one way and two will go another to surround you, their aim is just splendid, and other enemies are just as bad. If that's not bad enough (trust us, it is), you will get next to no health, you will get next to no shields, and you will get next to no ammo. You'll find yourself reloading from your last save because an enemy you really needed to go down in two shots took you three and that means there's no surviving the next room. Prepare for areas that would be nothing in any other game to take you days to beat. But that really brings home how Badass Jedi are, when you get your saber and suddenly stormtroopers go from death incarnate to beneath notice.
 * Some will agree that there is one truly bad level in Jedi Knight: Jedi Academy: the one where a giant worm bursts forth and insta-kills you if you step on the sand. Luckily, you are allowed to skip one mission in each of the three segments of the game, and this and the other (slightly less, but still) annoying missions are roughly evenly distributed across the three segments. Other much-maligned levels include the one with the invincible Boba Fett and the ones with the invincible rancors.
 * The level where you lose your lightsaber is pretty bad. Considering the game discourages you from using anything but your lightsaber except in rare cases (enemy Jedi always dodge guns, and regular enemies are much easier if you cut them down while deflecting their attacks), it's such an abrupt annoying change in gameplay.
 * Star Wars Battlefront II has several unbalanced maps, but the worst offender is Polis Massa, where the CIS/Rebel faction spawns soldiers in the hallway ahead of one of their starting command posts. This makes it nearly impossible for the Republic/Empire to hold on to their forward base even early in the match and extremely difficult to recapture, cutting down their reinforcements and making it very difficult to win. The Republic/Empire's best strategy for winning is to actually capture the CIS/Rebel bases from behind and let them have their own starting bases, reversing the imbalance, but it's extremely difficult to pull off. Capture the flag mode on this map is a little more popular for multiplayer....but it still lags really badly most of the time.
 * Naboo. The way that checkpoints are arranged means that your entire army will be bogged down in a messy and difficult battle for the centre, meaning you'll have to try to take and hold the rest of the map alone while also helping defend the centre.
 * Hoth, if you're playing as the Rebels. In theory, it's well-balanced, with both sides having access to vehicles, the Empire having more powerful weapons and the Rebels having better bases. The problem is that the vehicles aren't balanced unless there are two Rebel players. The airspeeders are able to take out the AT-ATs using the tow cable attack from the film. This is virtually impossible unless the airspeeder has two players on board as the AI rarely pulls it off. In other words, the Empire has two almost-indestructible weapons platforms which it can park in front of a Rebel base.
 * Even if the AT-ATs don't get you, Imperial troops can enter the base from the back. Trying to defend the base while everyone else is out trying to fly airspeeders is difficult, and doing so gives the Empire a chance to move the AT-ATs into position and spawn troops from them (yes, they can do that as well). And if you survive that, the Empire will control most of the map by this point and be able to regroup before you can grab any other command posts.
 * Not to mention the final mission on campaign mode "Hoth - Our Finest Hour."
 * Specially the very last part when you need to get a beacon for an orbital strike and place it on the trench just below of a Corellian Cruiser, the whole area is protected by auto-turrets and infantry, once you reach the target it is necessary to hold it there for a minute and prevent the rebels from destroying the beacon (if you fail, you must play the whole mission again).
 * The worst part is how the AI gives priority on killing you first ignoring all of your allies in the process, Regardless of difficulty setting. Although, it is most probable that your reinforcement count is already low by that point, making little to no difference when it comes to numbers.
 * The Tantive IV mission. Where to start? The corridor battle? The AI's inability to recognize that it's safer not to join Vader's attack? The fact that the commander's instructions contradict the actual method of capturing Leia?
 * Geonosis. Good lord, Geonosis. Don't capture command post on hill? DEATH. Don't destroy enemy vehicles? DEATH. Forget the Geonosians (which don't count towards reinforcements anyways)? DEATH. Play as the CIS and not be god-like? DEATH.
 * Honestly, about every other level after you beat Grievous counts. Anyone else really felt like Order 66 was a good thing after playing that mission? Only good part is that at least on that one you still have Clone Commanders.
 * Endor as the Empire, my god. Ewoks everywhere so small that you can't see them in the grass, they can pretty much one-shot you and if you do kill them they don't count towards reinforcements and just keep spawning. Traps against your major vehicles that makes them nearly useless. Even If you survive through this there's still your allies that fall like flies. And the AI of your troops is so horrible that you don't win even if you kill half of the enemy's reinforcements.
 * The first Star Wars: Battlefront is just chock full of fun multiplayer levels plagued with horrible AI.
 * Bespin. The tunnel is where your lovely AI teammates go to get slaughtered. Not only is the enemy AI accurate to a range of 10 football fields with shotguns (instant DEATH), they spam grenades into the tunnel that your teammates are loafing around in to reduce your spawn counter. The problem with this is that you share deaths with your teammates and despite you going 14-0, you can still lose due to all of your teammates going 0-14.
 * The Rhen Var Ruins was horribly unbalanced. Basically it was set up as a small but multi-layered map. Doesn't sound so bad until you realize that Dark Troopers/Jet Troopers can simply use their jet packs to take over most of the map before the other side can even get there.
 * Shadows of the Empire has Ord Mantell. First off, you have to jump from train to train; if you miss a train, you lose a life. If you fall off, you lose a life. This is made worse by two facts: First, you've only played one first-person shooter level to this point, and secondly, it wasn't the last one.
 * And then next is Gall Spaceport. Once again, there are way too many chances to fall to your death just because there's No OSHA Compliance at any of the numerous Imperial installations. Of course, similar to Jedi Outcast, it and the rest of the game generally experience a jump in quality (and fun) once you find the jetpack.

Unreal

 * Unreal. The second visit to the Skaarj spaceship, just before fighting the Queen. This time around, the power has gone out, leaving you fighting nothing but Skaarj with shields and larvae in a cramped environment pitched in complete darkness. It doesn't help at all that, of course, ammo and medkits are extremely rare. If your upgraded, unlimited-ammo-but-scrappy-anyway laser pistol skills aren't top notch, expect to die a lot.
 * Unreal Tournament. Five words: Xan Kriegor on DM-HyperBlast. Not only does the level take place on a small space cruiser where it's very easy to fall off and die, Xan himself can make this utterly and incredibly frustrating, as he'll likely obliterate you the first time you face him, and his favorite weapons can very easily knock you off the ship and into the abyss of space.
 * The worst part of it being that Xan likes to hide, making it a violent hide-and-go-seek. And a very fatal one if you fail to constantly look behind you. Made easier by Xan's constant spewing of taunts, though.
 * Another offender, from the Deathmatch ladder, is DM-KGalleon. Intricate as hell, narrow passages, a lower floor where dodging is almost difficult, and with all kinds of obstacles. Combine it with the ladder rule of weapons not staying (this is, someone picks up a weapon, and everyone has to wait until it respawns) and your enemies being more focused on killing you than among themselves, and you have a hell of a level.
 * Unreal Tournament 2004 has HyperBlast2 as one of its maps. It's a widened version of the original, meaning that you need to move a bit more to hunt down Malcolm, who never taunts you through the entire map. Even on the lowest difficulty setting, he will religiously pound your ass..
 * Aside of it, there's DM-1on1-Desolation from the Qualification ladder. That's right: the fourth level of the SP. It has almost all of the same issues as KGalleon, except that you compete against 5 bots and the weapons stay in their place when someone touches them.
 * Nothing in UT2K4 touches the final Assault map. Yes, not even the One-on-One with Malcom at the end. You and your team have to infiltrate a Skarrj mothership, including taking out its outer defenses and getting into its tiny entrance bay via spaceship, where you can and will be aggressively shot down from every possible direction before you can retaliate. If you do manage to get inside, you'd think things would get easier once you're on your feet in familiar gameplay territory, right? Wrong. Expect to spend ages respawning over and over again trying to evade the AI's Instant Insta-Kill Rocket Launcher Attacks of Insta-Death long enough to wear down each fanatically guarded node before the timer runs out (and, in the case of the last ones in the control room, even reach them at all). Destroying the reactor core and completing the offense portion is a miracle in and of itself; when the enemy attacks they will be sure to bring their AI of Doom with them, rendering your defenses helpless as they slowly tear through the very defenses they made nigh-impenetrable before. And this is on the easier difficulties.
 * Unreal II the Awakening, the second level is titled Hell. It's set in a factory on a cold planet. The memorable part? The. Enemies. Are. SPIDERS!!! Tiny ones that attack in groups as they crawl up to you & huge ones that leap across the room at you. To a player who suffers from arachnophobia, they will find themselves in a spot of trouble in Hell.

Call of Duty

 * There is a Russian mission in Call of Duty 2 which pits you against a German tank with no rocket launchers, meaning you have to literally touch it and plant an explosive charge on it. And the tank ignores all of your allies and only shoots at you. And the tank is always looking at you. Always. You can't sneak up on it because it can see through walls.
 * Even worse, there's three of them, and unlike everything else you have to use explosive charges on in the entire series, they're not stuck in one place. They can and will run away before you can plant the explosives, and they can and will run you over when you're trying to hide from all the other Germans constantly ventilating you.
 * For that matter, the last part of "Holding The Line", the second British mission. Once again, rather than just finding Panzerschrecks or something and destroying the tanks normally, you have to call in artillery fire on them from a roof. This is where the problems start. Your compass just points you towards what building you need to direct the artillery from - your only indication of where the tanks are is vague directions from Price and MacGregor. Again, they can run away between you calling in the strike and the shells hitting. And, there's still the constant stream of German soldiers pouring into the town, meaning you also have to watch the ladder to the roof, because if any enemies make it up there they will kill you and God knows Price and MacGregor won't actually put any effort into saving you.
 * "Mile High Club," The Stinger level in Call of Duty 4: Modern Warfare, is a Timed Mission set on an airliner. There is not enough room to move, the Mooks outnumber you, the rest of your team won't move up until you clear the area, and if you're going for the "Mile High Club" achievement, you die in four hits and only have one minute to reach the hostage, who you must rescue with a headshot; if you go for a kneecap, the level ends with the message "Veterans only get headshots." If you make one false move, you'll either die or fail anyway because you wasted time. It's the kind of level where you don't need a walkthrough so much as choreography.
 * Where do you begin with the defense of the Ferris Wheel? To set it out for those who haven't played this level; You and your injured superior have to fight off at least a hundred respawning enemies all armed with fully automatic rifles for 6 minutes while waiting for a helicopter to arrive. You have 5 Claymore mines to defend your ally with, and if he dies, game over. Luckily, most of the enemies go after you, instead of him. If you stay behind the Ferris wheel, which makes very good cover, attack dogs spawn in packs, which instant kill you unless you press a button in a 0.1 second window of opportunity. If you stay almost anywhere else, you get a rain of grenades. Have fun.
 * While not exactly that one level for the most part the level Hunted in Modern Warfare makes up for the rest of the level in one 'short' part involving a helicopter. During this one part you have to take out a bunch of people and then get into a barn to be able to advance, now overall this really isn't all that hard, even on veteran. But what makes it hard is they give the helicopter a gun. To put it lightly the helicopter is a bitch. On veteran it will kill you in about a second if you are not constantly in cover. Now if this still sounds easy, think again, the helicopter will move to make sure that you never have very good cover. And then there is the part where you have to leave cover to get to the barn, which you can't just charge into otherwise you will die. So you have to patiently sit outside the barn while the helicopter kills you and you do the whole thing all over again. Really it comes down to whether the helicopter decides to be stupid and move behind the barn.
 * One last factor that deserves a mention here is the hilarity of finally making it safely into the barn just to get plugged in the face by the three shotgun-wielding enemies inside who up until now had been hiding out of sight. Enjoy starting over. Again.
 * To clarify this further: The helicopter may look in another direction, but the instant it has line of sight on you, it will flick it's gun around INSTANTANEOUSLY and begin shooting you. It shoots no one else. Not to forget the Heat mission, going down the hill. The second runthrough on veteran makes everything else seem like a walk in the park. Although hunted is easy if you sit near the dodge-em cars as the enemies only come in a narrow corridor and you can just spam fire to get kills. And you get a pack of dogs to help you too if you're not a cruel bastard.
 * The beginning of "Shock and Awe" had you manning the helicopter's mounted Mark 19 grenade launcher while you approach the city. A minute into the mission you come to the bridge with enemy infantry and anti-aircraft gun nests a little farther on. Having a very limited angle at which you can turn the weapon as well as the necessity of watching an overheat meter while shooting in rapid succession, you will realize you die repeatedly exactly at the same moment simply because you can not aim at the hostiles who are just a hair outside the gun's operating area even if you try (and try you will). While during other strenuous missions you are able to switch tactics, in this assignment you are either bound to succeed or taking a cold shower. On Veteran this quickly comes down to being infuriated at seeing the same scripted stretch of desert as you approach the same spot again. And again. And again. The hint?
 * While "All Ghillied Up" is overall an awesome mission, there's one part that's hell. It's the part where you go prone in an open field while a convoy passes right next to you. There's one soldier in the convoy that almost acts as if he is programmed specifically to head right for you and discover you. If you lay down anywhere other than right behind MacMillan (sometimes even when you lay down there), he discovers you and you die.
 * "No Fighting in the War Room" on Veteran. Namely the part where you have to go through a silo on either the left or right side; as you walk past you near-instantly get shot-up from both sides, the worse part is how blatantly the AI in the side areas is boosted; you can kill everything down the middle without too much trouble at all with a little care, yet the enemies in the side areas instantly mow you down with about 90% accuracy at any range. Pretty much the only half-way reliable way to survive is spamming assault rifle grenades down the corridors; hope you didn't waste too many earlier!
 * In the followup game, Call of Duty: World at War, the level "Heart of the Reich" is now infamous among players on Veteran mode for it's insanely overdone difficulty, unfair gameplay and sheer luck required to complete it. Grenade spamming, endlessly respawning enemies, enemies that can shoot you through large amounts of rubble, all you need for your controller breaking rage.
 * The fourth mission, 'Vendetta'. One spot in the opening, an Enemy at the Gates ripoff, brings the entire game to a SCREECHING halt in Veteran mode and racks up several dozen deaths on your part: the duel with the German sniper. The sniper who can kill you with one shot, no matter where you are (unless you're behind cover) or where it hits you, whose bullet seems to fly just slightly less than the speed of light as it hits you as soon as you see the muzzle flash, making your own chances of aiming near impossible, whereas he can absorb THREE FULL SHOTS ANYWHERE ON HIS BODY and remain not only alive, but able to shoot with the same inhuman speed and precision, all the while Reznov pretty much completely lies to you by claiming he's on the second floor, only for you to look and get shot by him on the THIRD floor because Europeans don't count the ground floor as the first and you're playing in America.
 * "Blood and Iron". Unlike every other tank mission in the series, which were incredibly awesome, this one just manages to be endlessly infuriating. Infinitely-respawning enemy soldiers launching Panzerfausts nonstop. And unlike the usual for this series, they're really infinitely-respawning - even when you destroy the radio tower they're trying to defend they still keep coming, constantly shooting you with Panzerfausts, preventing you from focusing on anything else, preventing you from actually regenerating your health, preventing you from completing the goddamn mission.
 * For Modern Warfare 2 there's "Takedown," with enemy gunmen coming at you from every angle imaginable, from behind, windows, rooftops, everywhere. The complete lack of anything providing half-way decent cover makes this an absolute hellhole.
 * And having to do it solo too! (Both operators accompanying you are almost inevitably killed very early on.) Part of the frustration of "Takedown" is that it's not that linear and actually very easy to get lost in near the end. Worse yet, you go through all of this, and your reward?.
 * Or "The Hornet's Nest," which picks up almost immediately after "Takedown." While it's more linear because you at least have your team accompanying you (except for the last part) and the early portions are fine because they take place at longer ranges with clear lines of fire, the close-quarters fighting in the market stalls is hell, with enemies coming at you around corners, or it being difficult to find targets through all the miscellaneous stuff strewn around the place. Can you believe that the omnipresent danger/being fired at from everywhere was supposed to be a selling point for these levels?
 * Which gets even worse if you attempt the challenge associated with that map: killing twelve juggernauts (Heavily armoured supersoldiers that could most likely 1v1 a tank) using only claymores and your knife. Let it not be forgetten that to fully complete the challenge you also need to do this on the highest difficulty and that Juggernauts are the only enemy in the game that will survive a melee attack. It takes 6 or 7 DIRECT hits from the claymores...to kill ONE.
 * "Second Sun" solely for the office cubicle fight on any difficulty. First things went to hell fast at the beginning of the level. Then your optics don't work throughout the level -- the Red Dot and Holographic Sights have no aiming dot, and not even the ACOG Sight has a crosshair. Night vision goggles, as unhelpful as they usually are due to the lack of light-sensitivity adjustment? Right when it's dark enough that that wouldn't be a problem (from lights pointing your way washing out the picture), the NVGs are down too. And that's all before you're forced into an extremely-close-quarters shootout in a cramped office space with only starlight and muzzle flashes for illumination, with both frag grenades and flashbangs (aka "complete screen whiteout and ringing in your ears" for a few seconds) going both ways, and both your lines of fire and movement being interrupted by the fact that you have little office cubicles and mini-partitions all over, with the sides of the room pretty much forcing you to go straight forward or backward other than through the partitions or a few side compartments on the left...
 * "Loose Ends" is the definitive That One Level on veteran, the defense of the house itself turns out to be pretty easy if you find the right position to camp (although it's easily this if you don't), but the true nightmare comes when you have to escape; there are tons of enemies from every angle, and they spawn when you are out in the open (so there's very little chance to thin their numbers). So, in the end, pretty much all you can do is keep running and using flashbangs it until you hit the point where the scripted sequence that ends the level starts. That everything after the house defense was all for naught just makes it worse.
 * The Gulag. Good luck getting bullets from the front (mercenaries), from the sides (the same mercenaries), from above (damn mercenaries shooting you from the upper passages) and from the ground (Last Stand enemies). And that's before you find the riot shield soldiers in the middle. Add to that the flying grenades from both sides, the fact that riot shield users get to shoot through the shield (which you CANNOT do), M1014s for close-quarters combat, their ungodly aim and the friendly fire @ 100% (meaning you can easily kill your teammates) and you have a level that'll make you pull your hair even on Recruit.
 * And if you think "Loose Ends" is bad, immediately after you get "The Enemy of My Enemy." Recap: Soap are sent to Afghanistan to look for Makarov. Shadow Company attacks. You're told to let Makarov's men and Shadow Company fight it out as much as possible, but they're all way too eager to drop the ongoing battle with the guys sent to kill them and start shooting at the unaffiliated Brit in the ghillie suit (read: you).
 * None of which touch the Spec Ops level "High Explosive." To wit: You, either alone or with a human teammate, fight in the same favelas complained about above against fifteen Juggernauts. They absolutely earn their name, as they carry M249 machine guns, wear full bomb-disposal body armor, and run only slightly slower than you. You are only give explosive weapons to kill them, which is extremely annoying because, as noted, you are in an all-close quarters level. Then, as you get going, they start coming at you two and eventually three at a time.
 * Another pain-in-the-ass spec-ops level is "Homeland Security." Beating it is quite an accomplishment even on Recruit, basically you have to defend a small town from FIVE waves of enemies. It's not so bad at first as you have plenty of claymores and auto-firing turrets to help you out, but those will get used up pretty quickly on every wave after the first, you have to deal with a MOTHERFUCKING PREDATOR DRONE that will constantly be bombing the crap out of you every single time you set foot outside a building, and if that wasn't bad enough, later waves also have BTRs and helicopters you have to deal with. You can't just camp out at one location as you'll have to get more RPGs from other buildings to take out the choppers and BTRs, it becomes REAL easy to get overwhelmed by the sheer number of enemies and the drone since it's random which building the enemies will spawn from, which makes it nigh impossible to consistently defend one location. So you'll more then end up running between buildings while dodging gunfire from enemy soldiers, choppers, BTR's and those damn Predator missiles. It's a LONG exercise in pain and frustration, especially if you run out of RPGs on on the last wave and have NO way to take down that last helicopter or BTR. Don't even THINK about trying to beat it on Veteran unless you're a real masochist.
 * "Time Trial". Literally the only thing that can make you fail is running out of time, which you can get more of by passing in between flags. Your snowmobile will not allow you to pass in between flags - you literally have to slow nearly to a stop just to get it to turn in the direction you want without crashing into something and turning the other way or just plain missing your target.
 * Call of Duty: Black Ops gives us Rebirth. The first part of Hudson's portion (where you ride in the BTR) isn't that bad, but when the be prepared to die. A lot. Your suit can only take so much damage, it doesn't repair after a while unlike regular bullet damage, and if your suit breaks, you die instantly. To top it off, the fog of  obstructs about 90 percent of your view, so you constantly have to rely on using your Infrared Scope to shoot enemies, and by the time you've spotted them they already will have put about twenty-nine holes in your face. Trying to beat this part of the level alone can be straight-up insane, but if you're going for the Achievement for making it through this part of the level without dying, it will most likely make you want to tear your hair out. And did we mention that after Hudson clears the Nova, there was an undiscovered crash bug that would even give your X-Box a Blue Screen of Death?
 * The mission Excutive Order is this. The 1st part of the level goes by ok, but then you get to a part where you have to go into some tunnels. Tunnels with bad guys that spawn forever, almost no checkpoints, and you die in about a second. Have fun.
 * And what's worse is that your two invincible buddies with unlimited ammo barely do anything to help. There are times where you may purposely die because you just spent all your ammo and still can't move up.
 * Because of the way the level's laid out (lots of cover and respawning enemies) you'll need your GP-25, frag grenades, and Willy Pete smoke grenades to advance at all. Guess what you run out of before you're two-thirds of the way through the battle.
 * The mission SOG also gets an honorable mention for throwing the NVA at you. The entire NVA. It's relatively easy until you reach the downhill segment, whereupon an endless wave of NVA will shoot at you from about seven different positions (including the armory on your right) and won't stop respawning until you reach the checkpoint at the base of the hill. In order to do that, you have to use two barrels of kerosene with claymores taped to them to cut off their advance. The game doesn't give any obvious hints to use the barrels except a subtle and barely-audible audio cue from Woods. The subsequent uphill fight through a burned forest is almost a breather.
 * And shortly after SOG comes Numbers, where you're chased by Spetsnaz over the roofs of Kowloon, getting shot at from literally every direction you can possibly be shot at from at any given time. About the only good part of the mission is its music, and even that could wear thin when you have to play the same segment 15 times in a row.
 * Numbers gets even worse if you're trying to get the achievement for only using dual-wield guns. Sure there are plenty of them available, but they are inaccurate and there are several segments that pit you up against enemies who are well out of the effective range of your handguns/machine pistols.

Other

 * Magic Carpet, level 49 of 50 features a realm in which the player must do battle with a hundred fire vomiting wyverns, and just as many lightning breathing griffins, as well as the pissed off and already maxed-out wizard, Vodor. Until you figure out the appropriate, and convoluted strategy, this level is nearly impossible as the wyverns will level your castle before you gain the appropriate spells to battle them. You gain spells by filling your castle with mana, which you do by killing enemies and possessing their souls. Unfortunately for you, the wyverns spread out at the start of the map, and eventually wander into your hometown and burn it to the ground, allowing your rival to relieve you of your mana as it explodes from your shattered, burning windows. The last level is easy by comparison.
 * Medal of Honor: Frontline, the "The Golden Lion" level on Hard. Lots of snipers and enemy ambushes, alarms triggering more such ambushes, Rail Shooter truck ride sequences where it's hard to aim at enemies, health items are few and far between, the lack of in-level save points and Demonic Spiders-type behavior of many enemies on Hard exacerbates things.
 * Nijmegen Bridge, too. Snipers on top of the bridge girders, endlessly respawning waves of enemies, lots of enemy hiding places, machine gun nests, all made harder to see by the fog.
 * In Allied Assault, Sniper's Last Stand, aka Snipertown. A town full of extremely well-hidden insta-hit snipers that take off massive amounts of health per hit. If you thought that was bad, it gets worse in the second part, where you have to escort a squad of suicidal chipmunks through the whole mess.
 * The Command Post has unavoidable alarms that continually "teleport in" enemies behind you, and respawning guard dogs during your escape. This is where the game hits a brick wall on hard difficulty.
 * The Proving Grounds in Bioshock. It was a fairly unique shooter up until this point, and then the producers go and throw an annoying Escort Mission at us.
 * An Escort Mission that was unique in the depth of guilt trip it laid on the player. You could fail this repeatedly without gameplay consequence, but watching a little girl die while a mournful motherly voice underscored the tragedy of it seemed far worse than restarting it from the beginning.
 * Everything post-Central Command could really count. The slums and the Little Sister facility are both compelling and scary, but the big emotional climax of the game is gone, and the levels just drag on and on...
 * Siren Alley in Bioshock 2. A sudden spike in difficulty (especially if you're playing on Hard) combined with being totally fucking creepy makes for one fun level. Why is it creepy? Dead strippers, a peekaboo wall revealing a woman being dragged away to be raped, some nasty atmospheric music and a church service with dead people in the pews to start...
 * In FEAR, we have several.
 * The last level at Armacham. The entire Armacham mission arc is more or less made up of nothing but a series of those one levels for various reasons, such as having scarce resources, high numbers of enemies, labyrinthine design and no map, or having to face many walker units. The last one is unique pain because you are already weakend from the previous missions, but you still have to press on. There isn't much health or ammunition, and to top it all off, you face a rather long section full of nothing except for flying robotic drones which are small, hard to hit, have flawless accuracy, do a good amount of damage, take a fair amount to kill, and don't give you anything back.
 * One of the levels where you are in the streets is pretty damn tough. You have to kill multiple walkers, vans full of enemies, and some extremely mind-fuckey Alma hallucination sequences that are dark so that you can't see much while you have to kill swarms of enemies.
 * Project Origin has its own fair share. As a rule, anything on Hard once you get to Wade Elementary School. However, certain levels stand out on their own regardless.
 * The Nurse's Office mission is hard, but all the sections once you reach Halford count.
 * The subway+/sewer levels definitely hard. They feature rather frequent appearances by mooks with heavy weapons and upgraded durability. Your best saving grace is that ammo for the semiautomatic shotgun is common here.
 * The train level is seriously a major bitch too. It starts off with you being on a train and having to deal with repeated attacks by the best damn Elite Mooks in the game. They're intelligent, skilled, and work in squads. There isn't much cover available, nor are there many helpful items like armor or medkits. Oh yeah, and while this is going on, you occasionally have to run around the train and stop it from derailing. Then after that comes a nice segment where all you have to worry about are ninjas who actually are in a dark, confined environment this time. So after you've cleared through them, you get not one, but two fights with snipers! You have to kill a small group of snipers in order to access a switch, and then you have to kill a much bigger group of snipers in order to get onto the second tram. There are at least 20 snipers in all and they're pretty good at their jobs. Now that this nightmare is over, take a breather, listen to some exposition, and face sexual assault from Alma, who decides to jumble up the map, making you have to work a maze.
 * The last level is a combination between this and Best Level Ever. On one hand, you get to use the APC's turret to mow down the Replica, who have been making your life miserable since almost the beginning. On the other hand, the final fight is trippy to Eva levels. Oh, and it features an enemy who can multiply exponentially the longer you take to win.
 * The Kamchatka levels in Soldier of Fortune II: Double Helix certainly qualify. The enemies have armor-piercing bullets, the grenades they lob come out of nowhere, and many times in the outdoor areas you can't see the bad guys until its too late.
 * Two words: Temple Ruins. The level where it is most obvious that The Computer Is a Cheating Bastard. On higher difficulties, the enemies are all Demonic Spiders who can magically detonate grenades before they're supposed to go off, have pixel-perfect accuracy at ridiculously long range while your weapons have "prodigious recoil"(Marathon 2 manual) and can hardly hit a target, have "x ray vision" through smoke and foliage, etc.
 * The final level of Condemned 2: Bloodshot is just all-around annoying, what with Mooks everywhere, limited health pickups, a frigging helicopter you have to fight and enemies with special powers who cause your screen to go blurry as Ethan (your main character) holds his head in agony as a shrill, irritating noise rings in your ears.
 * In addition, Black Lake Lodge post the bear sequence seems to fit this trope for a lot of gamers, as it abandons the normal horror gameplay for a little while in favor of disarming bombs and busting caps in SWAT guys Tom Clancy-style.
 * Star Trek: Elite Force 2 has an extremely long and complex sequence where the Enterprise-E is assaulted and starts taking boarders -- constant shootouts with the threat of being blown to pieces, a sudden control change midway through, and several impossibly timed missions that involve a ridiculous amount of intricacy add up to what is essentially the biggest escort mission ever.
 * The flying levels in Turok: Evolution. The game's controls are awkward and unresponsive at the best of times, but for some reason they're much worse in these levels, the view's Y-axis is inverted and cannot be adjusted, there's an invisible ceiling with variable height that sends you stalling into the wall (and insta-death) if you hit it, clipping glitches, low-res textures that make it difficult to judge distance... and almost half of the game is made up of these terrible levels.
 * The final level of Serious Sam: The Second Encounter, the Grand Cathedral. Despite the undeniable Crowning Music of Awesome, the level takes the game's War Sequences so far that it becomes positively Nintendo Hard. The Great Pyramid, final level of preceding game in the series The First Encounter, is slightly less bad on this account. Of course, being subjective and all, some others consider them Crowning Levels Of Awesome.
 * Serious difficulty, especially with extra enemies, can make Metropolis, Alley of the Sphinxes and Karnak to be That One Level in the First Encounter and Great Pyramid is relatively easy compared to them with that difficulty. Metropolis because the first part, there are numerous ambushes at every step you take forward and towards the end you get huge waves of enemies. Alley of the Sphinxes because at the beginning of the level, most of your ammo has taken away and until the final arena, extra ammo is scarce. Karnak gets the biggest difficulty increase because in serious difficulty, very tricky enemy placement occurs with many places being full of arachnoids using their hitscan weapon. A lot of the dangerous fights also take place in a small confined arenas.
 * Red Faction, late on, squares you off against enemies with an instakilling hitscan gun that shoots through walls. Mandatory savescumming, much?
 * What's more annoying is that when you get that same gun, your enemies gain the ability to know when you're lining up a shot at them through the wall and too often step aside just as you fire. And that gun has a very slow reload cycle. And of course you never get any warning that someone's lining up on you with it, but they do.
 * Vietcong has quite possibly the most realistic "sewer" level of all time, take that as you will. There are levels where you're forced to go into underground tunnels to fight Vietcong soldiers, and the tunnels are extremely small and cramped, forcing you to crouch most of the time, your teammates won't follow you in meaning you're constantly looking over your shoulder to make sure an enemy doesn't one-hit-kill you from behind, it's incredibly dark and everything looks the same, there's multiple paths with no indication of which path is the right path meaning you'll often go in circles looking for the exit, and to top it off many of them are filled with one hit kill booby traps which are hard to spot in the dark. What makes matters worse is that there are three of these levels, and each of them are thirty minutes long at least, and one of them has underwater sections where it's quite easy to drown if you don't know what you're doing. But at the very least they're not the stealth missions of the sequel Vietcong Fish Alpha, don't even get me started on those.
 * Postal 2: Apocalypse Weekend, the Military Base. Your entire inventory - guns, ammo, and items - is taken away at the start. This happens a few times throughout Postal 2, the only mandatory time being at the Brewery on Wednesday, but in those cases, you can recover your whole inventory on your way out. Here, all that you can find are a few Standard FPS Guns. None of the interesting Postal weapons, save the weak throwing scissors, and a sledgehammer near the very end, which would be nice as it's normally a one-hit kill. However, the vast majority of the enemies are heavily armed and armored soldiers, and their helmets make them immune to the sledgehammer. Add to that the fact that there's very few health pickups and even less armor, and it essentially becomes an exercise in saving and reloading until you get lucky and manage to survive.
 * From the Eternal Damnation mod, the museum level. Two very large rooms packed to the gills with all the zombie types up to that point with very little health or ammo stashes. Unless you've saved up a considerable amount of ammo at this point or gotten yourself a good melee weapon like the axe, you're going to have a very tough time beating this level; especially against those tall zombies who absorb bullets like nothing else in the game.
 * Rainbow Six: In the Eagle Watch mission pack, there's Lion's Den. Involves rescuing hostages from a clock tower full of snipers that can shoot at you from ridiculous angles where they are nearly impossible to hit, ie they can aim straight up and down, while you can't. And if a certain one notices you, he'll trigger a bomb.
 * The titular finale is even worse. You have to rescue hostages from a an even more heavily sniper-guarded room. As usual, they have near-flawless accuracy, and there's also countless Mooks patrolling the hallways, determined to slaughter any AI-controlled teams.
 * From Vegas 2, the Nevada Desert level. Even with your teammates being incredibly retarded, at least they were good at attracting bullets otherwise meant for you. Here, you have none of that - your only support is an NSA agent who isn't even physically with you and is entirely useless. Your ability to call in thermal scans to see where enemies are is gone. You cannot stealthily pick them off - kill one and everybody's instantly alert to your presence.
 * Descent's 6th, 11th, and 19th levels, especially on Insane difficulty. All are composed mainly of tight corridors infested with deadly Demonic Spiders such as Homing Missile Hulks, Vulcan Drillers, Plasma Drillers, and Missile Platforms. Level 19 in particular is considered to be the hardest in the game, with its circular passageways allowing roaming enemies to flank you from any direction. And you don't get to recharge your energy for a long time. It doesn't get any easier at the reactor room, where there's a half-dozen Red Hulks and Heavy Drillers with nowhere to hide (although there's a hard-to-reach Invisibility Cloak).
 * The first game's Level 6, where the deadly Class 1 Drillers are introduced with a vengeance. You're guaranteed to lose at least two lives on the higher difficulties. Not to mention the Teleporting Keycard Squad of six Drillers that attacks you at the red key.
 * The end of Level 16. A large chasm with two Matcens(Mook Makers) generating Drillers and Hulks, half a dozen Red Hulks, followed by narrow passage to the reactor room that is guarded by two Missile Platforms and two invisibility cloaked hulks. Nigh-impossible on Ace and Insane, unless you go for the invincibility powerup behind the Driller-generating Matcen.
 * 'Fall of Berlin' in Battlefield 2142. Sure, as an online-only game the problem is only as severe as your opposition, but this level is just badly designed. PAC start bottled up a one end of the map and have to either capture an extremely exposed control point or sneak a squad through extremely linear and open streets in order to get behind EU lines and break the ticket drain. And if the EU bring their battlewalker and APC up to the Frontline flag and PAC can't destroy it (very difficult if the drivers know what they're doing) PAC might as well give up immediately. The entire battle will be spent with them being killed without breaing out of their own spawn area.
 * What makes it even worse is that even if PAC do manage to break out and capture some flags, the exceedingly linear design of the map means that both teams spend the rest of the battle running up and down capturing and losing the same few flags, which is hardly the definition of fun.
 * The Silo is by far the hardest level. Six or so buildings that you have to capture, infinite snipers in the windows of said buildings, lack of cover, and you have to Hold the Line against mortar crews from the top of the silo.
 * Golden Eye Wii has its moments of That One Level. The Bunker level and the Cradle level are probably the worst offenders, difficult to complete even on Operative level. The Bunker is the lesser of two evils compared to Cradle, where the big boss JUST. WON'T. DIE.
 * The Snowy Bridge from Painkiller. Enormously long, full of enemies, and the snow level on top of that. The nadir is probably the section on the top of the aforementioned bridge, where the ground beneath you is very slippery, and the enemies seem to never stop coming.
 * The second Be More Objective challenge in Brink, almost every objective is right next to the enemy spawn. So even when you clear the area, you're going to get bumrushed in a couple seconds anyway.
 * Not to mention security day six. Only two real routes to the first objective, both of which can be closed off by rebel engineers, the first objective being tedious, and annoyingly long to repair, and the worst part is when you get to the end, and you are the only one trying to stop the missile from firing.
 * From NOLF 2: A Spy In HARM's Way, the level "The House Where Melvin Used to Live" features infinitely spawning ninjas, and a very finite amount of ammo and healing on the ground. Normally, you'd be able loot supplies from dead enemies, but on this level, they vanish immediately after you kill them.
 * Duke Nukem Forever's penultimate level, Blowin' the Dam. It's entirely underwater, so you have to swim from bubble stream to bubble stream. There's several Octobrains, which often appear between streams, forcing you to either kill them extremely quickly or just try to bulldoze past them and kill them later. To top it all off, it ends with the Energy Leech, the Duke Nukem version of the Boost Guardian; a boss that sounds easy, but is so infuriatingly cheap that you'll want to eat the disc.
 * Payday: The Heist has, for Easy Difficulty, Heat Street, which will more likely than not result in somebody getting downed a few times the first few times it's done on easy. Most people will then figure out where the best cover is and then it loses it's edge on Normal. Green Bridge, the last mission available on Normal, is Heat Street but much more difficult, requiring you to make a mad dash to one location THROUGH AN ENDLESS ASSAULT to survive. Even on Normal, people can get screwed over by the Luck-Based plane pickup section (If you get it on the first balloon, you are in for a lot of problems.) Both of the two Hard/Overkill missions have already been beaten on Overkill, complete with video proof. Neither of these two, as of this writing, been cleared on Overkill on-camera.
 * In the game XIII, there is a level where you need to defend a cabin from a seemingly never-ending wave of enemies for a certain period of time. Sounds fun, right? Wrong. When you are in the cabin, you cannot leave it under any circumstances unless you want to get ripped to shreds by the helicopters and snipers. Even worse, the enemies can break down the cabin, leaving you with no cover at all from the snipers. You can find the strongest gun in the game in the same cabin beforehand, but you can only supply ammo for it (and all your weapons) two times. As if that weren't bad enough, there's only one health pack in the mission. And if you die at all, you need to start the whole level over again.
 * While deep in the D6 Missile Silo toward the end of Metro 2033, you and Miller must cross a room full of Amoebas and the pores that spawn them. Miller will shoot the Amoebas, but not the pores. Good luck.
 * Operation: Temple Gate in Rainbow Six: Rogue Spear. Goal: rescue hostages from an opera house swarming with terrorists. Several snipers guard from the theatre balconies, other tangos patrol back and forth, and if any in the theatre see you, they will shoot the hostages dead.
 * It gets worse with Stone Cannon in Raven Shield. Although there are no hostages, it consists of a maze-like series of warehouses, with, in addition to the large number of patrolling tangos, an abundance of alcoves, sniper ledges and windows for them to pick you off from.
 * Tron 2.0: The tank gauntlet on the Antiquated Server. Jet must run through a gauntlet of tanks that are read-only (you can't shut them down) and indestructable (you can't destroy them). So, not only are you having to run and jump through a glitching obstacle course with tanks shooting at you, the tanks will occasionally and randomly shoot out the very ground you stand on.