Disc One Final Dungeon

"Fake Ending: There will be a sequence which pretends to be the end of the game but obviously isn't--if for no other reason than because you're still on Disk 1 of 4."

- The Grand List of Console RPG Clichés

"Thank You Mario, but Our Princess Is in Another Castle!"

- Mushroom Retainer, on Bowser's Castle

Every Disc One Final Boss needs a home, and that home is the Disc One Final Dungeon. Somewhere between the Noob Cave and The Very Definitely Final Dungeon is a suitably epic fortress/castle/ruins/cave/space station that could feel like The Very Definitely Final Dungeon, if it wasn't at the end of the first disc out of four. This dungeon can be anywhere from the first quarter of the game to just before the end, as long as it's epic enough to fake you out into wondering if it'll be the final dungeon, or at least give the characters a strong impression of that. The Disc One Final Dungeon is usually longer than previous dungeons, though that isn't always the case, and always culminates in The Reveal.

To clarify, the dungeon doesn't necessarily have to be a true fake-out to the player. Obviously, when a multi-disc game has an epic dungeon at the end of the first or second disc, it's probably not the last one. Still, for all the characters know, this is the final showdown with the Big Bad.

With the advent of higher-storage capacity mediums (DVDs, Blu-Ray discs, and internal hard drives), the ability for developers to successfully fake out the player with Disc One Final Dungeons has been restored to SNES-era levels. As a result, more savvy players will start looking for other indications that the game isn't over (unanswered questions, empty inventory slots, locations not explored, etc).

See also Interface Spoiler, for a similar Meta-spoiler effect.

This is obviously a spoiler trope, so read at your own risk. And please refrain from turning this thing into a river of unnecessary spoiler tags.

For a similar phenomenon in literature or TV, see Spoiled by the Format.

Action Adventure

 * The return to Hyrule Castle in The Legend of Zelda a Link To T He Past. You have the three MacGuffins and the magic sword you need to face the assumed Big Bad, but that's only the beginning.
 * Likewise, once you get all three known Plot Coupons in Ocarina of Time, and the titular ocarina that will let you get that same sword, you think that a big battle will be coming forthright. Instead, you just get put in stasis for seven years, by which point Ganondorf has taken over Hyrule Castle and you need six more Plot Coupons to get there.
 * And then there's the top floor of the Tower of Spirits in Spirit Tracks, in which you.
 * The Ghost Ship in Phantom Hourglass. It's suitable for the final dungeon, because Tetra is there, but you still need three more items and you haven't explored half of the ocean.
 * The Forsaken Fortress in The Wind Waker. You got all 3 pearls and the Master Sword. Now you're going back to save your sister and defeat Ganondorf. Oh wait, the Master Sword is unpowered and worthless. Now you have to get more items, do 3 more dungeons, get the Triforce of Courage, and then defeat Ganondorf.
 * Okami is very guilty of this. The game leads you to believe that Orochi is responsible for all the evil present in the world. Oh wait, it's only all the evil represented in a small area of the world. Exploring the rest of the world leads to Oni Island, and an epic dungeon where you meet the Lord Of Darkness. Surely that's the end? Nope. That's maybe 2/3 of the game. Good luck getting to the final boss in this one!
 * The Underground Ruins in Okamiden are even more convincing. You've got all the brush techniques and you've explored the entire map. Also, the supposed final boss has a Humongous Mecha poised to destroy the world and kickass battle music. But after beating him, the true Big Bad appears and the game heads back in time. Later, the Moon Cave Nine Months Ago serves this purpose, seeing as the Big Bad headed there, many more plot threads have been resolved and there is a Point of No Return. However, it's not the last dungeon. Clever of Okaimden to use the first game's disc one final dungeon as a disc one final dungeon.
 * Castlevania: Symphony of the Night "ends" in the throne room. Which is where all the other Castlevanias ended so this must be it, right? Right?
 * Aria of Sorrow also leads to a boss battle in the throne room. Then you get a tomato dropped on you.
 * Order of Ecclesia had Mystery Manor. You go there to
 * Legacy of Kain: Soul Reaver has the Sanctuary of the Clans and the Pillars of Nosgoth, the throne of Kain's empire and where you finally fight him after several hours of gameplay. Of course, you haven't even acquired the game's titular weapon by this point, so...
 * In La-Mulana, the Shrine of the Mother can and must be visited midway through the game, and is in fact where the final dungeon will be. You can make an optional trip to the room of the Final Boss, which contains a message from Lemeza's father saying that he couldn't wake her. Only after all bosses except Mother are defeated is the level transformed into the final dungeon.
 * The second visit to Ocean Force Point in Star Fox Adventures. You've got all the Spellstones back in place, Fox, but there's still that little matter concerning the Big Bad and the Damsel in Distress.
 * Kid Icarus: Uprising manages to pull this off spectacularly  And you're not even halfway through the game!
 * And just when you thought you could relax, knowing the rest of the game is going to be about fighting  The game pulls another twist on you only two chapters after this one

Action Game

 * Karoshi 2 does this about four times. After the 50th level, there are eight boss fights in a row, each one after the first claiming to be the final one of course (culminating with "I Bet This Is Not the Final Boss..."), after which it gives you a fake credit roll, and a "the end", sign, then it takes you to a Breather Level where the spikes run away from you, followed by another fake credit roll and a "really the end" sign. The game then closes, and reopens a few seconds later with "fooled you again". You then have to complete six "Super Karoshi Kart Racing 2000: Extreme Awesome" levels. And yes, there is a fake "thanks for playing" message (followed by the Awesome Smiley). AND THEN you have to complete this weird level called "Shadow Of The Bossus". You then get a screen with your character and a giant spike, which fades out to black and gives you the real credit roll, then a white screen, then a "thanks for play" screen. The only way to escape from this is to press escape, which takes you to the main menu, except that now, none of the buttons work. Pressing escape again gives a message saying "it's not over yet", and then fades back into the level with the giant spike. Touching it allows you to fly, and flying out the top of the level leads to a heaven level with a heart and a spike, simply saying "choose". Touching the heart gives a final pink and white screen with "the end". And yes, it's real this time. Touching the spike, however, sends you to Purgatory in the form of the first level from the first game, over and over and over again.

Beat'Em Up

 * Teenage Mutant Ninja Turtles III: The Manhattan Project for the NES does this to you, despite being a side scroller beat-em-up. Level 7 is the Technodrome. Prior to this, the Technodrome had always been the final level in any Ninja Turtles game. You fight Shredder at the end, beat him, rescue April... and then he runs away, giving you 3 more levels. The Very Definitely Final Dungeon is Krang's spaceship.

Fighting Game

 * World Circuit serves this role in the Wii version of Punch Out. Even after Little Mac escalates into the categories of the World Video Boxing Association and gains the title of champion boxer, he has to defend it by fighting all of his previous opponents, leading to the notiriously difficult Title Defense mode. This mode itself has a second example of the trope with the World S Circuit. Even after proving himself worthy of the champion title, Mac has to keep fighting until in Last Stand mode.

First-Person Shooter

 * Bioshock had Rapture Control, where you face Andrew Ryan for the first and last time, and have no choice but to kill him. Instead of a Final Boss, it's a cutscene that borders on a Mind Screw when you find out just how Fontaine has been controlling you all along.
 * Most of the dungeon part is composed of the preceding Hephaestus level, in which you try to find a way through Ryan's defenses as he taunts you with his 'accomplishments'.
 * Bioshock is an example of this Trope being given away mostly through Interface Spoiler.
 * The Cetan warship in Perfect Dark. In what might look like the ending cutscene, the heroes are preparing to celebrate when the villains of the piece invade the institute as one final act of revenge.
 * The first disc of Jedi Knight ends with the first boss duel, followed by a rather long escape from the evil fortress, culminating in the minor-but-personal enemy's escape.
 * Borderlands averts this pretty convincingly. The Crimson Fastness seems like it might or might not be the end of the game, but your level is only in the low thirties (out of a possible 50-69, depending on what patches and DLC you have installed) and there is at least one obvious boss still ahead of you (Commandant Steele). In actuality, it's the last true dungeon, followed only a run through a canyon to a cutscene where Steele is killed, followed by a (very quick) fight with the real final boss.

MMORPGs

 * Guild Wars has one of these in almost every campaign (Except for Eye of the North, which has rather small fake outs, it's told through three story arcs instead.)
 * In Prophecies, You finally make it to the Gates of Kryta...Well you've now made it. The People of Ascalon can finally settle in piece but...oh wait a sec, WHO Was that in the cutscene?! Well I guess now we gotta go help the White mantle!
 * In Factions, after getting the urn from the Kurzicks and Spear from the Luxons, you go back to thwart the Big Bad's plans once and for all. Only you still have quite a ways ahead of you...You haven't even explored the entire Canthan map yet!
 * Nightfall has an even greater one albeit this one comes about two thirds of the way through, and is an even bigger fake-out than the first two. You have gone to every single Region of Elona. now all that's left is The Ruins of Morah to take out Varesh Ossa. So you take the Climax Boss out and...and...AND....now you're in the Realm of Torment!
 * Well hey you wouldn't get a very satisfying ending otherwise...
 * In The Lord of the Rings Online, both Angmar and Dol Guldur qualifies. Both menacing places by their own, and in any other work, these places would certainly make for a fitting ending, but the actual ending will most likely take place in Mordor.
 * In Runescape, for free players, Elvarg's Lair can be this. Then you get membership, and find out that compared to the rest of the game, it was pretty much a Disk 0.1 Final Dungeon. It is later invoked again  in While Guthix Sleeps, but there's ANOTHER quest that plans to top that and finally give us the final dungeon for that questline.

Platform Game

 * Amazingly enough, this one goes back all the way to the original Super Mario Bros.. Games of the time were usually a short sequence of levels that would repeat ad nauseam, with minor tweaks to increase difficulty along the way, so imagine the surprise of a gamer weaned on Atari 2600 games who makes his way through world 1-4 only to discover that, not only did he not just rescue the princess, but there's a whole new set of levels to run through!
 * Both of the New Super Mario Bros. games have it.
 * The DS game apparently concludes on a normal looking castle at the end of World 8, with the boss being Dry Bowser. However, the boss music is the exact same boss theme you've been hearing when fighting the bosses at the end of each of the previous worlds. Further confusing matters is that upon dropping Dry Bowser into the chasm, you get the exact same sequence of Bowser Jr. taunting you and running off with the princess (just like when you cleared the previous worlds for the first time). Then the game returns to the map screen... and a bridge suddenly emerges, leading to six additional levels...
 * And another normal tower level at the end of those.
 * The Wii game had the Airship level in World 8 as the apparent final level. You've been chasing the same Airship the entire game, so it makes sense that the final level should take place there, right? Even Bowser Jr. ditched his ruined Koopa Clown Car for the bigger, original one... but the boss theme is no different from the first two encounters. After this, Mario (and/or whoever else if playing in multiplayer mode) finally meets Princess Peach on the deck of the airship. A good place to end the game indeed. One problem, though... BOWSER HASN'T ACTUALLY SHOWED UP IN THIS GAME YET!!! So of course Kamek reappears and steals Peach, and it's off to kick Bowser's tail in the final castle!
 * Also happens in Super Mario 3D Land.
 * "Bowser in the Dark World" and "Bowser in the Fire Sea" from Super Mario 64, "Bowser's Star Reactor" and "Bowser's Dark Matter Plant" from Super Mario Galaxy, and "Bowser's Lava Lair" and "Bowser's Gravity Gauntlet" from Super Mario Galaxy 2.
 * In Ratchet and Clank: Going Commando, the Thug HQ on Planet Snivelak may qualify. Red sky, lava, a level that's pretty much one linear path to a huge, ominous fortress, BGM that's MUCH darker than anything else in the game, a long It's Quiet... Too Quiet segment before having to fight your way through some of the toughest enemies in the game, all cumulating in a battle against the game's Recurring Boss in a massive Humongous Mecha to rescue the game's love interest. Is this the final level? HELL NO.
 * In Mega Man games, once you get to the fortress, each level is preceded by a map screen showing the various destinations you're headed for, ending with a special one that marks the Big Bad's location. In most games, once you get there and defeat the boss, an extra location appears that the map didn't bother to show you earlier. The fourth, fifth, and sixth games take a different route: there's another whole fortress after the one you're initially shown.
 * The Last Castle in Something Else. After reaching the end of the level, the game reveals that

Puzzle Game

 * Professor Layton and the Unwound Future. Big tower to climb? Check. Series of puzzles acting as a final exam? Check. Block sliding puzzle? Check. Yet there are still 5 chapters left.
 * Chip's Challenge appears to have 144 levels, but a password secretly sneaked in level 34 can provide access to the final levels.
 * Portal 2: Chell's encounter with GLaDOS after escaping from her test chambers and sabotaging her defenses. It's even at around the same time point for the Final Boss battle relative to the first game. Then GLaDOS turns out to be an Anticlimax Boss and the real Big Bad is revealed... and you've still got two thirds of the game left to go.

Role Playing Game

 * Chrono Trigger does it probably three times, in order:
 * The first third of the game is the lead-up to fighting the apparent Big Bad Magus from supposedly creating Lavos, but it reveals that Magus was actually trying to destroy Lavos.
 * The next is the Tyranno Lair: it seems as though your party is full, there are no more time periods to explore and that you're going to prevent this next apparent Big Bad from summoning Lavos, only for the game to reveal that Lavos is the meteor that wiped out the dinosaurs, and then the game sends you to 12,000 B.C..
 * The Ocean Palace is an even better fake-out, and eventually becomes the pseudo-final dungeon, but the first time you run through it's a final dungeon that turns out to lead to one of the most shocking moments of the 16-bit RPG era.
 * Chrono Cross also does it twice, with Fort Dragonia and Chronopolis. Fort Dragonia is particularly notable because it's the site of the dream you had at the beginning of the game, which itself felt like Storming the Castle.
 * And don't forget Terra Tower.
 * Although Terra Tower was the final dungeon. All that was left to do was to destroy the Oh, and find out 90% of the plot. A better example would be the Dead Sea.
 * Kingdom Hearts, for the final world you fight through a giant techno-castle, fight The Dragon, fight the Big Bad, and fight the Dragon again, and seal the Cosmic Keystone. Oops, we're looking for The Man Behind the Man, and the final dungeon isn't even a real world, within the game terms it isn't even in the same realm of existence.
 * Common in the Final Fantasy series:
 * The Giant of Babil in Final Fantasy IV. You've been all over the world, all over the underworld, and to the moon and back and are facing a giant superweapon that the supposed Big Bad had been collecting crystals to awaken, and are now fighting through that superweapon and a series of tough fights including a Boss Rush of the four elemental generals you took on through the course of the game. Then you get to the control room to face the Big Bad and it's Luke I Am Your Brother.
 * Even earlier than that, the Tower of Zot plays this role. You've been pretty much everywhere in the overworld, all four known crystals have been accounted for, and you go to a futuristic tower that's not even on the World Map to attempt a Hostage for Macguffin exchange and have a showdown with the Big Bad. Only afterwards do you learn about the underworld and the additional crystals.
 * Taken semi-literally in Final Fantasy IV: The After Years, where Golbez's tale starts in the previous game's final dungeon, and he even fights as his end-of-chapter boss.
 * Exdeath/Exodus/X-Death's Castle in Final Fantasy V. It's a large, terrifying castle where the Big Bad hangs out (complete with fleshy organ-like walls with ribcages and tortured fiends built right in!). You've already conquered the two worlds of the game and been everywhere, so it only seems natural that this'll be the the site of the Final Boss battle; but when you finally destroy the shield surrounding it, fight your way to the top and clash with Exdeath himself, he completes his hitherto unknown plan to merge the two worlds together sending the light warriors unconscious away from the castle and with a whole new patchwork worldmap to explore.
 * In Final Fantasy VI, the Floating Continent miles above the earth, where the assumed Big Bad, Geshtahl, and his assumed Dragon, Kefka, are trying to get the powers of creation would seem like a final dungeon to most players. Of course, the inclusion of a completely different Feelies map labeled "World of Ruin" was sort of a tip-off.
 * The Northern Continent in Final Fantasy VII. You've already chased Sephiroth around the world, so it's easy to think that these ancient ruins could be the final showdown. Of course, this is just the end of the first disc.
 * It starts even earlier than that. The whole trek in the Shinra HQ feels like a huge climax and then the real game begins when you first step into the world map.
 * Final Fantasy VIII. Maybe we'll stop the sorceress by shooting her at the big parade. Nope, just kidding. Hey, giant showdown between our floating university and her floating university! Sounds like a climactic way to end the ga--no, just kidding. How about on this weird floaty "Lunatic Pandora" thing? Not quite, but getting there. The second one technically does involve the defeat of the villain, but you learn there that someone else was behind it all along.
 * The entirety of Terra is a third disc final dungeon in Final Fantasy IX. This is where Kuja and The Chessmaster behind him are from, so it must be important, right?
 * Zanarkand in Final Fantasy X. It's the end result of your very linear quest, with Big Bad Sin at the end of it, right? Hmm... well, not so much. Sin is, in fact, the final dungeon...
 * Also made tricky by the fact that Tidus is narrating the entire game in flashback form UP TO Zanarkand, which may lead you to think that when the flashback meets up with the current time, you're about to face your Final Boss...
 * Final Fantasy XI: as an MMORPG with a few expansions by now, the plot has expanded as well - what used to be the final dungeon in the original game on release became the prerequisite for a new mission line that was made available when the 1st expansion was released.
 * The Pharos Lighthouse in Final Fantasy XII. We're talking a 100-floor dungeon with all sorts of boss fights and a giant Green Rock at the top. Admittedly the real final dungeon is much smaller (you can't even save inside it) so it's more of an anticlimax.
 * In Final Fantasy Tactics, the assault on Fort Zeakden is the final confrontation with the Death Corps and signifies a major turning point in Ramza's life (and depending on how much Level Grinding you did can be a serious challenge), but it's only the last battle in Chapter One.
 * It's also part of one giant flashback from Ramza, so really, no one should have been fooled in the first place, especially since the first battle in the game takes place a year after the Fort Zeakden battle.
 * The run on the Palamecia halfway into Final Fantasy XIII has all the trappings of a final dungeon: a final powwow with your comrades before starting the mission, fast-paced music that plays continuously through exploration and battles, former bosses taking you on in groups, and so on. Finally, you get to the ship's bridge and prepare to face down the apparent Big Bad and his Dragon... Only to have the former kill the latter in front of you, allow you to "defeat" him (ostensibly to make sure that you're progressing fast enough to fit in with his plans), and then send you on your merry way to what you've been told is hell the entire game. Oh, and you unlock the ability to customize your party.
 * Made more evident if one read the handbook, which has a section on cei'th missions for once you reach Pulse. And yes, it does say the missions are on Gran Pulse.
 * In Tactics Ogre:
 * Barnica and then Heim, since they are rather large areas you are sieging. Coritane castle as well.
 * Kuihuai Tower in Shadow Hearts. Evil wizard is trying to do some very very big and bad evil magic, the forces of good are getting together at the very place where they fought him before, and now... there's an entire new part of the world for you to explore while you hunt the real Big Bad.
 * Shadow Hearts Covenant had Idar Flamme, the final dungeon of the last game, and Apoina Tower, the first tower you woke up in and the place you go to hunt down Astaroth at the end of the first disc. Once again, there's a new part of the world for you to explore (which happens to be the region where the first half of the original Shadow Hearts took place). This happens to be a classic example of this trope since this game is one of the few Play Station 2 games with 2 discs and the aforementioned dungeons appear at the end of the first disc.
 * Murderworld in Marvel Ultimate Alliance originally appears to be the castle of Doctor Doom, the game's Big Bad. It's not.
 * Star Ocean the Second Story builds up the first showdown against The Omniscient Council of Vagueness in a suitably epic flying fortress stocked full of Lost Technology...then an Earthshattering Kaboom happens and you get warped to the world where the Big Bad came from and have to try to prevent them from attempting the same on this one.
 * Neverwinter Nights's Plague campaign, after chapter 1 but before chapter 2, there is an interlude chapter. In fact, the entire sequence on how to defeat the boss here is practically a dry run on how to defeat the final boss of the entire campaign. As you have to go through the same steps of destroying the invulnerability givers to make the boss vulnerable.
 * Lunar: The Silver Star had this in the form of the Frontier and the Grindery. You fight your way through the Magic Emperor's fortress of doom, gather your forces and finally stand against the Big Bad himself at opposing ends of a bridge. Then... there's a lot of talking. Looking up screenshots, the Magic Emperor says during the conversation, "This isn't the time for our final confrontation, dragonboy! As any dullard with an ounce of culture knows, that time is reserved for the third act!" The bridge separates, and the Base on Wheels heart of the Grindery drives away, requiring the full party to chase it. And disable it. And scale it. And confront the Big Bad again. If you're playing one of the remakes, it turns out that the Big Bad you fight here is Actually a Doombot - the Big Bad is alive and well, and the real, real final dungeon is The Fortress of Althena!
 * Act Four of Jade Empire consists of the player character, having found all the pieces of the MacGuffin, storming the Imperial Palace to confront the Emperor. After you defeat the Emperor... well, suffice to say that Act Seven consists of the player character, Back From the Dead, storming the Imperial Palace to confront the Emperor.
 * In Dragon Quest VIII, the Dark Ruins. This is so effective in mimicking a final battle, in fact, that the game's real final battle, involving zooming, swooping shots of the night sky above the entire world, seems like an anticlimax.
 * Dragon Quest III pulls this with Baramos's castle.
 * Dragon Quest VII is probably the epitome of the Disc One Final Dungeon. If the game had been a single disc, you'd have no idea that was only the first half of the game. Unfortunately, there's still a whole other disc to go.
 * Dragon Quest IX has, which was actually fairly convincing as the final dungeon until The Man Behind the Man made himself known.
 * In Dragon Quest VI, you spend several hours trying to find Murdaw. Then
 * The Persona series:
 * Persona 3 attempts the Disc One Final Dungeon about three-quarters of the way through the game with the fight against Strega and the twelfth arcana Shadow, but it's very obviously not the end of the game, if only because there are still unanswered questions, and the in-game calendar still has about six months left on it.
 * Persona 4 pulls this twice, and actually succeeds because you have the option of getting a bad ending at those points if you don't choose to pursue the unanswered mysteries. More than a few people have rushed onto message boards to complain about the horrible "ending" without realizing that they were only 80% done. And before those is another dungeon that the characters think will end things, even if it's a somewhat clearer fake to the player.
 * Now Mitsuo's dungeon on the other hand, is unconvincing, everyone acts as though they are finally going to get the murderer, genre savvy players will note that they haven't even completed half the year the main character is meant to be staying. Or the fact that every other line he says makes it obvious he can't have been the murderer. Or that your characters and Personas at this point are around level 40-50, while attempting certain Persona fusions reveals the existence of Personas as high as level 60 or 70, implying the true length of the game.
 * Also helps to note that Mitsuo's victim had nothing in common with the others.
 * Tales of Phantasia has Dhaos' castle. You've explored the whole world in the past by now, and it's time to make the big guy pay. Only problem is you're just re-enacting the battle you saw in the opening, which means Dhaos runs away to fight another day. If only the party knew their Dhaos went 150 years ahead rather than 100.
 * Tales of Destiny. You have chased the Lens all over the world, tracked it down with the aid of numerous friends, fought several hard boss battles, and go through the end sequence... only to find out that half of the events of said end sequence were a Xanatos Gambit by one of your allies to imprison the Empathic Weapons and the Lens just got used in the NEXT superweapon of doom. Made more effective by the fact that the game is only one disk, and the Lens quest takes a while and involves everything on the box and previews.
 * Tales of Eternia has one at the mountain in Inferia. You're definitely not done yet considering you still got Celestia to explore now!
 * The game follows up with a disk two final dungeon in Balir's Castle.
 * The Tower of Salvation in Tales of Symphonia. It looks like the world regeneration is going to happen, but then...
 * And then the Tower of Salvation again...and the Tower of Salvation, yet again. The second and third are more convincing fakeouts because they take place on the second of two discs.
 * Slightly subverted in the Playstation 2 remake as it's only one disc. Nothing changes, however.
 * Tales of Symphonia: Dawn of the New World: Lezareno Building Number 2, despite leading up to a climactic battle with the head of the Vanguard, doesn't look like one at first, as the core he has would be, at best, your sixth. Then Lloyd does a Big Damn Heroes act, and suddenly seven of the eight cores are in the same place. And then you get done with the battle, Save the Villain from the influence of Solum's core, and find Lloyd battling Richter, who has the last remaining core. Could it be possible that you're about to get all of the remaining cores in cutscenes and this really was the last dungeon? Considering the fact that there's a cut scene every few seconds, this really wouldn't be surprising...but then Richter reveals Emil's true identity as Ratatosk, and the now not-insane Commander Brute reveals that Richter was the one who made the Vanguard into the militant organization it had become. Yes, the man whose actions the main character has been defending throughout the first seven chapters is the real Big Bad.
 * Tales of the Abyss: You've killed the Big Bad at the Absorption Gate and this last section is a playable epilogue a là the old King's Quest games, right? ...Yeah, not so much. This one was given away pretty quickly, though, since the pseudo-ending sequence included a pan over areas you hadn't been to yet that were very obviously playable dungeons because of the visible, unopened treasure chests.
 * Tales of Vesperia has The Enduring Shrine of Zaude where the party confronts the supposed, but not so Big Bad, Alexei and defeat him, only to find that he had revealed something greater that would bring about The End of the World as We Know It.
 * The Genre Savvy player will, however, have noted that you were told of Adephagos but have not yet seen it, so that can't be the end of the game.
 * Tales of Hearts has the Imperial Special Operations Unit Base Nibelg. Up until now, the quest has been to restore Kohak Hearts' soul, and the commanding officer of Nibelg has the last piece. So you beat him, get it back, and heal her... and then it turns out The Dragon is still alive... and then the Big Bad shows up...
 * Tales of Legendia does this three times. The first, the Bridge, isn't so surprising because it's only chapter 4 and, even though you're fighting the supposed Big Bad, there haven't been any Mind Screw plot twists yet (and there definitely are). The second, the Wings of Light, is a bit of a surprise. It's the end of the main quest, but you've still got the character quests left to go, which give insight into the rest of the party. And then it does it yet again with the penultimate dungeon, the Wings of Light in Grune's character quest. What's interesting about Legendia, though, is that the real final dungeon, the Cradle of Time, is actually quite short. If it weren't for all the huge battles right in a row, it wouldn't feel like a Very Definitely Final Dungeon at all.
 * Tales of Graces has Baronia Castle as the Disc One Final Dungeon. The party's main objective is to aid Prince Richard in overthrowing his evil uncle and becoming king. At that point, you probably are around the level 20s, and are at least 10-15 hours in the came. The typical Tales (series) average level should be around the 60s for the final boss, and about 30 or more hours depending on if you do sidequests or not. In addition, there are many unanswered questions as well, such as the mysterious origin of Sophie as well as . So when
 * Then the game fools you again with the Lambda Cocoon dungeon.  In other words, it's not over yet, sucker!
 * The Labyrinth of Time and Space in Star Ocean 1. Again, the Big Bad you're chasing for the entire game is at the end of it, so you'd expect it to end then, right? NUH-uh.
 * And you know, the name of the dungeon itself would kind of imply it.
 * The World Ends With You. After the initial (and obvious) Your Princess Is in Another Castle at the end of the first week, you could be forgiven for thinking the end of the second week would be the end...
 * Except for the fact that Beat hadn't been a playable character yet, and Manuals Always Spoil.
 * Solaris in Xenogears would count, if only for the epic battles, both played out and in cutscene, and the amount of information revealed. The only problem is how many questions said information raises, and the fact that you're still on the first disc.
 * One of the earlier examples of this trope, Phantasy Star has the Air Castle, abode of apparent Big Bad Lassic. The fact that the player must ascend the tallest tower in the game just to reach it adds to the illusion.
 * PSII had Climatrol. Nei killed in a Hopeless Duel Boss Fight? Check. The first boss monster seen in the game so far? Check. The fact that this is supposed to be the source of all the biomonsters? Check. And when you're done...NiceJobBreakingItHero.
 * PSIV had Zio's Castle. Made more dramatic by the fact that the namesake permanently kills off a character and the second fight with him is more of a revenge battle.
 * The Wild Arms series:
 * The original Wild ARMs had the Photosphere, lair of the leader of the demon invasion and supposed Big Bad.
 * Wild Arms 2 has Heimdall Gazzo, an orbital space station in a wild west setting - which is what marked the actual Very Definitely Final Dungeon of the first game. And it could have been the final dungeon itself if the developers felt like ending the game there, since the plot of the second disc centers around a mostly unrelated threat.
 * Wild Arms 3 does this twice. The first time The second time
 * Baten Kaitos: Eternal Wings and the Lost Ocean: Emperor Geldoblame in the Lava Cave. Wait, what do you mean he's not the Big Bad? Then
 * Pokémon Gold and Silver/Crystal and HeartGold/SoulSilver: you've beaten the Elite Four, so you--wait, what do you mean there are sixteen badges in all?
 * becomes this in Pokémon Black and White; normally after that part you'd battle.
 * Earlier,
 * from Pokémon Mystery Dungeon: Explorers of Time/Darkness/Sky. The game's real final level is
 * Fire Emblem: The Blazing Blade has Darin, marquess of Laus, who is the apparent villain, at least to the main characters. The characters know about Ephidel, the mysterious advisor who showed up and convinced him that a rebellion would be possible, so the fact that Eliwood's story has only been going on for nine chapters doesn't seem too suspicious--chapter 20 will probably be the battle with Ephidel, and then it will either all be over or it will move on to another story just like it did after chapter 10, right? Then chapter 19 ends and Ephidel introduces his boss Nergal, along with Nergal's plan to bring dragons into the world. And then, unexpectedly, Ephidel fails to survive the cutscene. In all fairness, Nergal had sort of been introduced before the start of Chapter 18, right before Leila got killed, but it wasn't unreasonable to think that this wasn't something that we'd have to worry about while Eliwood was the main character--perhaps Hector would be getting his own story. Turns out, "Hector's Story" is just an extended, tougher version of Eliwood's.
 * Occurs again in Radiant Dawn. There are actually FOUR seperate endgames.
 * Angel's Tower in Breath of Fire III. This is where Ryu supposedly learns the truth about what happens to the Brood (his race). Instead, this is where Garr tries to kill him as the Last of His Kind to offer to the Goddess Myria. Garr fails, Ryu becomes the Kaiser Dragon for the first time, and escapes. After that, the Time Skip kicks in.
 * The Saturn game Albert Odyssey: Legend of Eldean (the only one in the series to get an official translation) has what looks to be the final boss only for the game to begin again with a Time Skip and another story arc. The giveaway here wasn't in the disc count, since it's a single-disc game, but the fact that at least three of the characters profiled in the manual haven't been introduced yet.
 * Baldurs Gate 2 has Spellhold, the place where the Big Bad has fled to and you have spent the entire game trying to get too. Not the final dungeon after all...
 * The Obelisk in Shin Megami Tensei Nocturne. True, it never once pretends to be the Final Dungeon (although it later becomes the entrance to it), but it's obvious the game's coming to a major climax here, considering: 1. It's the hardest and longest dungeon in the game so far, 2. It's the tallest tower in the Vortex World ("closest place to Kagutsuchi") and Nihilo's most highly guarded area and 3. It's where your teacher's, the person you've spent the entire game up until now trying to find, being held hostage. The Assembly of Nihilo earlier in the game could also count.
 * From Strange Journey: Sector Eridanus. It's where the Vanishing Point--the link back to Earth--is located, and you fight a difficult two-part boss here.
 * Legend of Dragoon manages to have several examples for the first disc. The tree where the man who killed Lavitz's father is holing up with the dragon who attacked you in the opening? Not the end of the disc. The assault on The Alcatraz you had visited previously, which the major villain Freugal runs, and also where  Not the end of the disc. The actual final dungeon of Disc One happens to be the castle of Emperor Doel, who appears to be The Man Behind the Man for Lloyd, and who just so happens to be
 * And this is only the FIRST Disc. There are still 3 other discs FULL of examples. Picking one: The is fought in the second disc. End of the disc? OF COURSE NOT! That's only 1/3, damn it. You still have to fight 5 other examples of Disc One Final Dungeon bosses just to get through disc two.
 * Legend of Legaia does this many times.
 * The first fake out is Zeto's Castle; You have all three characters, it houses the source of the Mist that corrupts the land, and Zeto even has a battle theme not heard prior.
 * The second major fake out is Zora's Castle. You've gone through all 3 regions, explored nearly every corner of the world map, and the final Mist Generator apparently lies within, flying high above the world, but
 * The final Mist Generator lies in Jette's Fortress. After the fight with the  final boss, you return to your hometown as the saviors of the world. Everything appears to be over, but it isn't until after clearing another dungeon that you head to the Very Definitely Final Dungeon...
 * The battle against Luca Blight in Suikoden II could qualify, minus the dungeon part.
 * The Forgotten Planet in Sigma Star Saga likely qualifies. In addition, it's also that one level and it wasn't playtested very well.
 * Mt. Lavaflow in Fossil Fighters. You go there to dig up the fossil of an incredibly powerful being from long ago, in order to defeat another incredibly powerful being from long ago resurrected by the apparent Big Bad, who is otherwise Nigh Invulnerable without a counteracting force, and afterwards which you will go on to the final Inevitable Tournament and become a Master Fighter. But you're not done yet; oh no. Not even close.
 * Champions fakes you out in a similar fashion when you go to the Bare Bones Brigade Base to confront Don Boneyard. Much like the BB Bandits from the original game, however, he serves as merely the halfway point, and introduces you to the game's real Big Bad,
 * Mario & Luigi: Partners In Time arguably does this with the first(?) time on the Shroob Mothership. It doesn't help that the fight with  just before entry was quite difficult.
 * The original game has two of these, Woohoo Hooniversity where you fight Cackletta for the first (and only time in normal form), and Joke's End (the big climax after restoring the Beanstar).
 * Super Mario RPG has an example too - Bowser's Keep. The game plays it up as the big climactic showdown and it isn't helped by the fact that many players (and game magazines) mistakingly think Exor is Smithy - you've still got another whole dungeon to go through after you beat him. Bowser's Keep does contain most of the games Infinity Plus One Swords, though.
 * Seiken Densetsu 3 has the Mana Holy Land. You've gotten every elemental spirit, and all three Big Bad factions have congregated at a single magical island in another realm. This has to be the end, right? Nope, just the halfway point. Interestingly enough, the real Final Dungeon actually is the Mana Holy Land, just much later on in the game.
 * The first Golden Sun game ends with the defeat of the Big Bad Duumvirate after they went One-Winged Angel on you in the Venus Lighthouse. You think the games over, the threat's ended - sure it was only the second lighthouse, but you won ... right? Wrong - you're told by your best friend/antagonist Felix that he'll continue Saturos and Menardi's quest in their stead, even though it seemed like he was being forced to help them (he was very reluctant whenever he appeared). Not to mention that Alex is still alive ... Then the game deceptively ends, and you think it's a separate story. Turns out that it is - when you discover The Lost Age (the sequel), released two years later, you actually play as Felix, trying to light the remaining lighthouses. Alex, the ally of the Big Bad Duumvirate turns out to be both the (arguable) Big Bad AND The Unfought. Trust me, it makes more sense than it sounds. But the first game definitely counts as a subversion.
 * Arguably an inversion for the players--many playing for the first time were quite shocked to find they had just finished the game halfway through the story.
 * Except for the fact that you'd covered the entire map. The other continents had yet to be revealed at the time.
 * The Deep Roads expedition in Dragon Age 2 was set up as the 'this expedition'll solve all our problems' mission, and turns out to be just the final mission of chapter 1.
 * The seventh chapter of Disgaea 4: A Promise Unforgotten suspiciously declares itself the final chapter as the heroes storm President Hugo's mansion.
 * Chapter 15: Citadel Ghirlandio in Valkyria Chronicles. Previously, you dealt The Empire a crushing defeat on one of the major theatres of the war, and now they're well and truly on the run. All that stands between you driving them out of Galia for good is their main base, which you've seen preview of in omonous cutscenes throughout the game. Furthermore, the chapter contains two battles, one of which is the incredibly tough last stand of a Recurring Boss. (said boss isn't the Big Bad, but you actually fought him earlier, and he doesn't seem like much of a fighter anyway.) Welkin even gives the typical "This will be our last battle, I'm really proud of all you guys" speech before you go in. And yet after you capture the citadel and leave, congratulating yourselves on a job well done...
 * Mega Man X Command Mission pulls an excellent one in Chapter 9. You go to fight the Big Bad Epsilon, working your way through his base and even taking on Scarface. Epic battle music? Check. Multiple parts in the battle? Check. Heartless Angel-esque attack? Check. You defeat Epsilon, then a cutscene plays and you return to Giga City to go home... So you have to go through The Very Definitely Final Dungeon and fight through the franchise's signature Boss Rush, then another powerful boss, and THEN the True Final Boss.
 * Summoner seems like it's about to send you to the final dungeon shortly after recovering the four summoning rings, as Joseph's mentor Yago goes on about the Summoner and the Rings being bound together in one by the Forge of Urath - the flames of the Forge will not harm the Summoner, he promises... And Joseph proceeds to lose his hand in the Forge, along with his summoning powers,, and the game immediately grows 2.5 times longer as you have to rescue Joseph, heal him, and recover four more summoning rings and re-bind the demons of the first four.
 * Diablo III has this in Act III if you went into the game completely blind. The PC descends into Mordor? Check. Boss fight against the Big Bad who had been pretty built up for a good portion of the game? Check. However, after you beat Azmodan
 * Diablo III has this in Act III if you went into the game completely blind. The PC descends into Mordor? Check. Boss fight against the Big Bad who had been pretty built up for a good portion of the game? Check. However, after you beat Azmodan

Rhythm Games

 * In Space Channel 5 Part 2, the fourth stage has you dueling the Big Bad and trying to take him out with a surge of power from the ship's antenna just like the previous game... . It takes two more stages.

Simulation Games

 * Free Space 2 sets you up to fight the mighty Shivan Juggernaut-class ship Sathanas, as you have to take a bomber in to blow out its beam cannons so the Colossus, the pride of the GTVA, can tear it down without being blown apart itself. This comes at the climax of a lengthy campaign, and it's almost strange that the game sends you on mopping-up missions through the Knossos wormhole afterward... until you discover a Shivan transfer point where dozens of Sathanas ships are passing through, heading for GTVA space, and you've got a solid third of the game to go. Volition (who also made Summoner, mentioned above) loves blind-siding players with this trope.

Shoot'Em Up

 * The Sega Genesis shooting game Trouble Shooter does this, even starting to roll the credits before going to the final level.

Survival Horror

 * Resident Evil 3 Nemesis: Nemesis: You are informed that you can escape Raccoon City in the Clock Tower only to find out that Nemesis will come flying out with a rocket launcher, destroys the helicopter which was supposed to be your only way to escape, and to top it all off, you get infected. But don't worry you still live.

Wide Open Sandbox

 * The raid on Diaz's mansion in Grand Theft Auto Vice City, which appears to subvert the ending of Scarface (on which Vice City is very heavily based).
 * The Christ Crown of Thorns in LA Noire, an abandoned church (with a catacomb for bonus points) serves as the final showdown in the mission "The Quarter Moon Murders" against the Black Dahlia murderer which serves to tie up all loose ends in the Homicide cases. Cue the next-half of the game after the mission was completed.