Portal (series)/Headscratchers

Computers and cake

 * How does a computer eat cake anyways?
 * Digitally. Duh.
 * One byte at a time.
 * It doesn't. This is one of the things that drives GLaDOS insane.

Lyrical confusion in Still Alive

 * This is a bit of a stretch, but during the song, GLaDOS says that there is research to be done on those still alive. After she spent the whole song telling us that she was still alive. Ergo, is there research to be done on GLaDOS? And by who?
 * Killing everyone at the Enrichment Centre probably wasn't what Aperture Science wanted from her, so she could do with some improvements. But I thought she was referring to other test subjects - clones of Chell, or other people - that are still in the Relaxation Vault. (Which would be somewhere else, with the pod Chell was in moved to the testing course to start the test.)
 * I took it as a direct threat to your character, Chell, as she is the only one alive, and that she will preform more testing on her.
 * The alternate ending confirms ^^^ to be canon.
 * Portal wasn't originally going to have a sequel. Even Valve was surprised by how well it was received.
 * That didn't mean they didn't have plans. The retconned ending was the original, but it was cut. So the party recovery associate is more of a director's cut than a true retcon. They left hooks there, such as the song, just in case.
 * The lyrics say the research is for the people still alive, not on them. It would make sense that she's implying that the purpose of the research is for the benefit of everyone in general.
 * It says both. Last verse says, at least according the the end credits text, that there are experiments to run and research to be done on the people who are still alive. Before that, it was always 'for'.

Removing the neurotoxin

 * If someone put the Morality Core in GLaDOS to stop her flooding the place with neurotoxin, why didn't they stem the problem by removing the neurotoxin emitters - or the stored neurotoxin? Is it because the gas released isn't really harmful but GLaDOS wants you to think it is?
 * Presumably because there was still a need for the neurotoxin to be released in some eventuality, the morality core just prevents her from doing it to amuse herself. You don't rip out a fire sprinkler system if it registers a false positive once - you still want fire protection, so you probably replace your sensors.
 * Yes, I'm sure neurotoxin emitters would be very helpful. Like maybe if they were attacked by aliens.
 * Judging by some other lines she spouts, like "when I look out there it makes me GLaD I'm not you"; and the fact that one of Aperture Science's research ships vanished from the dock some time in Half-Life's past; it's actually reasonable to assume that during the events of Portal, the alien invasion has already happened. Considering that teleporters are now functional and the Hand-held Portal Device is safe to use, Aperture seems to have come a long way from the Borealis accident. and with all the Aperture personnel mysteriously gone and the lab in a general state of disrepair...
 * If the sprinkler system tended to kill everyone in the building I'd imagine they WOULD rip it out after one false positive.
 * Since GLaDOS is in control of the whole building, it could be that she synthesised the neurotoxin herself in the chemical laboratories, and released it through the ventilation system.
 * Or mayby wherever they hid had no way safe enough to the neurotoxin.
 * Let's go to an important point... remember who was their boss?
 * According to the Portal 2 comic, she had neurotoxin installed for science experiments involving Schroedinger's theory and cats.

Purpose of the Cake Sphere

 * Given the "spheres" are core modules to regulate GLaDOS behavior (like the Morality Core), why the hell does she have a "Cake Sphere"?
 * To bake the cake, of course. It's great, so delicious and moist.
 * Maybe it originally did something else? After all, I'm not sure why they'd want to put in a crazed-snarling sphere either.
 * They did what they must because they can.
 * Same reason why they made the Heimlich Counter-Maneuver and the Take-A-Wish Foundation.
 * The "cake sphere" is actually her intelligence core, it's just currently working on a cake recipe, also the angry snarling sphere is her emotion core AND IT'S PISSED.
 * Actually, the spheres probably AREN'T core modules. More likely they're addons that alter GLaDOS's personality. The ending song states that GLaDOS is thrilled at what you've done, which can only mean that she WANTED you to destroy the spheres.
 * Unless she was being sarcastic or lying to you again.
 * She said so herself in-game that she wanted you to
 * It's possible that at one point, Aperture Science test subjects really were rewarded with cake, which GLaDOS was in charge of producing.
 * Another interpretation is that the Cake Sphere is actually a "Knowledge Sphere". Toxic cake recipes just happened to be in her memory. Would also explain the math screwup and immediate cover-up.
 * It could be different aspects of her personality. She has an orb for her curiosity/kindness, a core for aggression, and a core obsessed with cake. Combine them together and you get an AI that is obsessed with cake and treats Chell with love, yet that love is twisted by her aggression that forms the basis for most of the humor in the game.
 * GLaDOS was originally designed to help work on a Fuel System Icing Inhibitor. How can any machine study Icing without a thorough understanding of the dessert icing so frequently appears upon?
 * Too bad they gave her a cake with frosting on. If only they'd hired a baker instead of just buying a cake at the shops when their de-icing system kept adding sediment-shaped sediment!
 * Actually the official core names are Morality, Curiosity, Intelligence, and Anger.
 * Maybe Cake stands for something?
 * To quote a line from the sequel "Science isn't about asking 'why?', It's about asking 'why not?" -> so WHY NOT put a "cake sphere" on her?
 * The sequel shows there's a whole lot of cores with seemingly-random functions (a core that recites Little-Known Facts, a core that constantly talks about space, a cut-from-the-game core designed to make her paranoid). Presumably, Aperture just threw them onto GLaDOS to see which ones'd stop her killing everyone.

G La DOS respawning Chell

 * Why is it that even when I've escaped the test chambers, even when I've destroyed her Curiosity Core so she has no interest in the testing anymore, even when she says she's deleted my brain-scan so I'm "struck from the permanent record", does GLaDOS keep respawning me so I can head out and tear her apart?
 * GLaDOS has told her fair share of lies, maybe this is another one. She may not even be capable of this deletion, but if it would get you to stop destroying her, she would say anything.
 * Or maybe you're not respawned at all, but rather a new test-subject, who also 'participated in the experiment'.
 * Maybe a Chell clone?
 * Where did any of you get the idea that she's "respawning" you?
 * ... when GLaDOS told us specifically that she has copies of Chell's DNA and will bring her back over and over again? There's a chance she might have just been trying to freak her out, but there's also pretty decent odds that it's true.
 * But that doesn't mean she is respawning you, it just means she can. What I don't get is why someone is asking "why does GLaDOS keep respawning me so I can head out and tear her apart?" If they're referring to coming back to the last saved point if you die, that's not GLaDOS respawning you, that's just a game feature so that you don't have to start all over again. And if they're not talking about that, I don't get what they're asking.

The Companion Cube

 * Why does GLaDOS keep saying that the Companion Cube isn't alive and why does she assume that I give a damn about that?
 * The New "Lab Rat" Comic by valve confirms alot of YMMV, Just Bugs Me, and WMG things: Rattman *HAS* the cube with him WHILE GLaDOS is destroyed by Chell. (She says this beacuse the cube is in fact still alive and GLaDOS is insecure
 * Look at the graffiti. It's shown several times that Chell's Mysterious Benefactor believed the cube to be alive. GLaDOS wants to prevent that from happening again.
 * Or alternatively, the whole point was to play with reverse psychology; make the subject who probably at the point is at least mildly disturbed emotionally to form an attachment to an inanimate object. The "mysterious benefactor" is probably a previous guinea pig, by the way.
 * From the game mechanical point of view, the Companion Cube was given so much attention because the playtesters tended to leave it behind, confusing them in the following puzzles.
 * And remember that GLaDOS was more than willing to use the Cube's "death" as mental ammunition in the final encounter. The mixed signals she sent ("It's not alive. You killed it.") were designed to confuse and upset Chell.
 * A more salient point is that the symptoms GLaDOS listed as being a common result of Enrichment Center testing ("superstition, perceiving inanimate objects as alive, and hallucinations") really ARE very common symptoms of prolonged isolation. In fact those symptoms are, almost word-for-word, among those listed by people citing studies of prolonged isolation. It's not much of a stretch to imagine that test subjects who had trouble and therefore took longer to get there, or people who've been through the testing more than once, would be feeling isolated and traumatized (from threat of danger and lack of food) enough to actually consider the Cube as something of a friend, if not actually imagine (like the Ratman did) that it really is alive.
 * You're going to tell me you've never had an inanimate object you cared about? A blanket, a computer, something? It's the same idea. Honestly I'm amazed it was only given one level; they could have used the Companion Cube from the start to build up an emotional attachment and make it all the more meaningful when you finally euthanize it.
 * Yeah, prior to playing the game I expected it to be present throughout the game as well, given how attached the fans were to it.
 * You do realize that it does not actually have nerves and cannot, in fact, feel.
 * Eight out of ten people on an independent ethics committee believe that the Companion Cube most likely cannot feel much pain.
 * And even if it did die, there's a warehouse full of the things. She could always get more.
 * The Companion Cube was only given one level because it was always intended to simply be part of the puzzle for that level; during testing, however, they found that people tended to try and solve the puzzle some other way. So, to encourage players to use the cube, they drew a heart on it. This strikes me as exactly the sort of solution GLaDOS would have come up with.
 * Of course, the Cube is large enough to have originally contained a person.
 * Err, a baby person maybe.
 * You'd be surprised at how small a space a person can be crammed into. Whether or not they survive is another story.

Weird interpretations

 * Exactly HOW MUCH/MANY DRUGS do you have to be on to even THINK about writing this?
 * I don't think it's supposed to be taken seriously.
 * I would love to believe that, but I've seen far, far worse than this and the author was dead serious. Among them, someone who claimed Joss Whedon constantly raped his wife. Because he made Firefly. So...if it's not supposed to be taken seriously, it's still fucktarded. If it is...It's just proof that radical belief in anything can reduce any sane person into a giant mass of stupidity and...and...twatiness. Yes. Twatiness.
 * It's a knock at an (actually very reasonable, well thought out and illuminating) feminist essay that talks about Portal as a feminist take on the shooter genre. Or at least, an examination of how portal differed from the typical hetero-masculinist shooter game. And no, this kind of thing isn't stupid. And if you think it's stupid, you're probably pretty dumb.
 * I dunno. It seems kind of dumb to me. I mean, to start off, Portal isn't a First-Person Shooter game. It's a First-Person Puzzle game, which happens to be made on a game engine originally designed for making FPS games. That invalidates the thesis right there. Then you get into all this Freudian bullcrap about guns being "phallic symbols" and all that rot. By that logic, just about anything that incorporates a cylinder into its design is a "phallic symbol". For example, how about a table leg? Or a can of mace? Or, hell, a fire extinguisher? My table lamp has a cylindrical neck; does that make it a symbol of a society dominated by men? No! It just makes it a practical, simply-designed table lamp. Cylinders are pervasive in all manner of objects we encounter in daily life, and that's because it's a shape that, geometrically speaking, is very dependable and has a wide range of versatility. Chell's gender doesn't matter. She has no lines, anyway, and no personality except for what the player decides she has. "Chell" is, simply, just a placeholder for the player themselves; the game is in the first person because third-person games are more detached from the player, but the plot of Portal is meant to be felt personally, viscerally. Would killing the Companion Cube have been so heart-wrenching if it was done from a third-person perspective? No. It wouldn't. (... In addition, the first-person viewpoint probably comes from the fact that that is, you know, what the engine is made and best-equipped for. No need to complicate things with external cameras when you're already abusing your physics engine in a million other ways.)
 * I've always called it an FPS Puzzle scifi Minimalist (but not anymore) game in space on earth. Usually, just a Portal game.
 * One other thing: in-game, Chell doesn't even have a name. The only place the name Chell is used is one sentence in the very end of the credits.
 * Also, his essay is factually incorrect; he states that the turrets have "clearly male" voices, despite them sounding like genderless 10-year-olds, he says that GLaDOS encourages Chell to form an emotional connection to the Companion Cube when she in fact tells her outright NOT to do this, and he basically implies that Chell incinerates the Companion Cube despite what GLaDOS says, when GLaDOS in fact requires the player to incinerate the damn thing just to progress to the next level! Also, guns are not penises! Let's take a look at what he's saying here: Guns, weapons created in order to be able kill a person from a distance is somehow the same thing as the male reproductive organ, which is an important part in creating new life? Am I the only one who sees the obvious, glaring flaw in his logic?
 * The gun is good! The penis is evil!
 * The part where he compares Chell tipping the turrets over to, and I quote, "The power of the feminine [overcoming] aggression without the use of force." Yeah, because pushing the turrets or hitting them with a goddamn metal box doesn't require any force at all.
 * It's funny because personally, I prefer to just rush in front of the turret with a cube as a shield
 * What were they smoking when writing that, and why aren't they sharing?
 * I think he's a troll, guys.

GLaDOS's sanity

 * Is GLaDOS truly insane, a master of psychology, or both at the same time IN A SCIENCE LAB ? And for that point... Is Chell mentally mature? She was in a "relaxation vault" which looks sufficiently much like a Human Popsicle factory... So maybe she's a daughter or an Aperture Science Employee hailing from the Aperture Science Bring Your Daughter To Work Day?
 * Sanity is a relative concept. GLaDOS was instructed to test the Aperture Science Handheld Portal Device, and wasn't given any ethical parameters under which to do so. She created a testing environment in which every function of the Aperture Science Handheld Portal Device would have to be used, with a suitable incentive provided for a subject to do so (survival). Everything in the game, even after Chell supposedly "escapes" is still part of the test protocol.
 * Or so GLaDOS claims...
 * GLaDOS never actually claims that it's part of the test. She seems shocked when you escape, after all. This means that she's not planning on your escape, and the test is "done". However, she's a masterful liar. That means she's faking the shock, and it's a Batman Gambit intended to disable the inhibition cores.
 * But we really have no way of knowing if she really was shocked or not. I think it cheapens the gaming experience to think that she wanted you to escape. There's also no way of knowing whether or not she really knew what the Morality Core was.
 * Sanity is relative to normal humans. GLaDOS isn't human. There is no reason she should act like one. She must have some semblance of humanity in order for people to relate to her, but making her so human as to be considered sane is going way overboard.

Incinerating the Cube

 * Why do you need to incinerate the companion cube in an Aperture Science Emergency Intelligence Incinerator — when there's an emancipation field at the exit that does the same thing?
 * You can't get to the emancipation field without destroying the Cube. GLaDOS wills it to be so. Why? The Cube can't be destroyed by a circumstance that is out of Chell's control, no, Chell has to push the button and drop the Cube into the Intelligence Incinerator herself, and watch as the heart-covered friend is dropped into the fiery pit, and know it's all her fault. Still that imaginary chance that Chell could have avoided it.
 * Because then there would be nothing to stop Chell from just dropping the cube and walking through the field without it. And G La DOS clearly states, "State and local statutory regulations prohibit it from simply remaining here, alone and companionless."
 * You don't see it burn. And you see it alive later. You do the math.
 * I think you mean 'intact'. I hope you mean 'intact'.
 * I don't think that's the same Companion Cube.
 * It's not. Use the glowing-ball machine to make burn marks on every side of the cube (don't worry, it doesn't harm it). No such marks appear on that other cube.
 * Do you really think it's impossible for GLaDOS to have given it a little buff-up? Just for the party? Perhaps by using an Aperture Science Emergency Depilitated Cranium Shiner?
 * Not at all. It would be an ASEDCS, and would not spell any vague (and incorrect) premonitions regarding Adrian Shepard. You can also tell it's not your cube at the end - if you lose your cube, a new one is dispensed from the dispenser, so GLaDOS just dispensed one of those. You can actually toss a Weighted Storage Cube (with cheats) into the incinerator - only the first cube is incinerated, and the rest simply stack up inside the incinerator.
 * Nonsense, it was merely a mistake on their part, they clearly meant the Aperture Science Emergency Depilated Overworked Cranium Shiner; the difference is important because it also massages the subject's cranium after a particularly stressful experience, such as being incinerated. The acronym is ASEDOCS, a clear reference to the excellent docking abilities of the Borealis. The disappearance of the cube and the stacking of susequent ones merely proves that the companion cube is fine; GLaDOS has the "incinerator" rigged to drop whatever is first dropped into it into the ASEDOCS, and isn't set up for other cubes, which then stack up.
 * The ending can't just pop in the exact same cube you were using previously.

Who places the turrets?

 * The turrets are tripods with a narrow base and a very high center of gravity. If Chell is the only one alive, and GLaDOS has run at least one other person through the course since the neurotoxin incident, how are the turrets set up? They only have three limbs, and their entire upper body is one piece, so if they tried to lift one leg to tilt another turret upright, they would fall over, and they couldn't climb upright on their own. Heck, they couldn't even walk without constantly adjusting their center of gravity in a controlled fall, like humans do.
 * It's shown near the end that turrets are transported and placed with a giant claw that has a network through the ceilings
 * You might as well ask how she set up all the experiments in the first place. She probably has some combat androids packed away somewhere to do the heavy lifting.
 * Evidenced by the new ending, the above is more or less confirmed, what with that thing dragging the protagonist away.
 * This troper always did wonder why she would have turrets placed in closed rooms in service tunnels... Did she think the neurotoxins wouldn't work?

The furnace

 * What was up with the "victory candescence", anyway? I mean, you've got your test subject testing out your neat portal gun, you've been nothing but helpful to her (well, except for making her destroy the companion cube, but even that could be forgiven with time), and then you put your test subject (and that portal gun you've been testing, btw) into an easily-escaped death trap. Thereby giving Chell the motivation to tear you apart and destroy you. Didn't she realize that she could have avoided all this if she had just given you the cake as promised and let you go on your merry way? Either this is all some kind of plan on the part of GLaDOS, or she is an enormous idiot.
 * Because the first thing she'll do is say how she was locked inside a laboratory by a crazy computer with no humans left, and Black Mesa, Apeture or someone probably shut GLaDOS down.
 * I note you mention the portal gun. I hope you mention it, since its the way for Chell to escape the death trap, not because you think the portal gun would be at all affected by it. GLaDOS mentions that it can survive the temperature.
 * It's mentioned because the portal gun is cool. Would you want to kill somebody who gave you that to try out?
 * That was her plan. GLaDOS is Still Alive, after all - the "cores" you destroyed were merely inhibiting her functions (remember that destroying the morality core enabled the neurotoxin emitters?)

The Morality Core and incinerating Chell

 * If the morality core prevents GLaDOS from harming you (presumably), and if she is in control of the facility, how is it that she was trying to incinerate you? Surely the morality core would prevent that?
 * She's put you into dangerous situations in the interest of "testing". Presumably the morality core has... loopholes.
 * Likely the Morality Core doesn't prevent her from putting you in dangerous situations, but only prevents her from directly trying to kill you.
 * Or maybe the Morality Core was installed to stop GLaDOS from flooding the facility with deadly neurotoxin...and nothing else.
 * Also, the actual backstory surrounding the Morality Core is a little vague. If the one she has in the game is the same one she has in the Lab Rat comic, then we have every reason to believe that it doesn't actually work at all, since she later obtained neurotoxin under false pretenses and proceeded to kill everyone but Rattmann. (This makes her waiting for you to incinerate it some kind of sick mind game on her part, probably intended to make you think that her losing her "morality" is all your fault). If another one was installed between Bring Your Daughter to Work Day and the events of Portal, then anything goes. Maybe it worked, and maybe it didn't.
 * Notice that in the Lab Rat tie-in comic, one of the scientists likens the Morality Core to a conscience. And what's commonly said about your conscience? It can be ignored.

Android Hell

 * What is Android Hell? Was there something I missed?
 * Filled with photocopiers apparently.
 * Er, yes? The turret course that Chell ran through was designed for combat androids (so GLaDOS claims). Android Hell may be a reference to Red Dwarf's Silicon Heaven, or it could just be two writers with similar tone coming at the same joke, being that the more complex and overdesigned AI becomes, the more human-like it will be, and thus the harder it will be to control - so we'll end up applying to them what some have very cynically suggested is a method for pacifying and controlling humans; i.e. religion. "Don't do this, or we'll send you to hell." All just because we wanted a smarter refrigerator (or machine gun, in this instance). It's a bit like the 'cheerful doors' gag in Hitchhikers Guide taken to the logical extreme. I, for one, can definitely see the unique minds at Aperture Science hitting upon that solution, considering they turned a de-icer into a murderously passive-aggressive artificial intelligence obsessed with cake.
 * Red Dwarf or Futurama's Robot Hell, either-or.
 * What bugs me is more of a weird fandom thing. Almost every site that offers fan theories on Portal takes the "welcome, android" scene, quotes it out of context, and starts forming ideas about how Chell might be a robot. GLaDOS explains in the elevator exactly why you're being called an android: the test chamber is actually a "live fire course" for military androids (or, she's just messing with you again. Whatever, it doesn't diminish my point. Which I'm getting to). It's a very clever bit of writing and a very funny scene. Stop ruining it for me with your crippling need to be seen as insightful/original on the interwebz.

Layout of the second half
"Freeman: That means there's NO POINT TO THIS WHOLE ROOM! "
 * What really bugs me about the game is that it doesn't really try to hide the fact that the second part (in the "factory" style) is just an obstacle course too. Most of it is filled with lots of GNDN pistons and, apart from a few cube transporting tubes and some offices, there is nothing that even suggests that it was built for a reason other than test your skills and the neat gun. Take for instance the huge room where you're suddenly surrounded by ten turrets, and you have to do a triple fling to reach the next area. Or the shaft where you're at the bottom and there are numerous pistons doing nothing but going back and forth above your head. Or the room with the six pistons which when you walk over them drop you into a room with three turrets. Why do people even think this wasn't intended by the Enrichment Center designers?
 * Not only this, but there are always conveniently located portalable surfaces everywhere you go. Obviously it really just is an obstacle course for gameplay value, but the immersion does suffer at this point.
 * They do?
 * People think it's intended by GLaDOS, who has complete control of all the pistons, turrets, and other components.
 * I think somebody's confused 'intended by GLaDOS' with 'intended by the developers'. Seriously, if you play enough games it starts to become reeeeally obvious that some mysterious force wants the player character to succeed. Sure, it could be interpreted as the antagonist, if you wanted to be that paranoid, but it's far more likely the designers. By my reading, GLaDOS just isn't smart enough to pull the gambit she/everyone here, for some reason claims she's pulling. I mean, that's half Portal's hilarity, that your antagonist so bad at everything, including convincing you she's not an antagonist.
 * Play Half-Life, I'm not entirely unconvinced it's not required to have at least ONE room of death in your company to be standards compliant (bottomless pit box smashing room anyone?).


 * It's Aperture Science. The same company that turned a fuel injection system ice inhibitor into an insane-by-human-standards AI who has complete control over the facility, and decided that the best way to go about creating a better shower curtain was by building a device that bends time and space. Why not build a room full of turrets like that? And that piston room is behind wire, so it might be intended to test the durability of things. Or it might be there because Cave Johnson wanted a room full of goddamn pistons.
 * Near the end of his life, the guy who founded Aperture Science became, somehow, convinced that time was going backwards, hence, the neurotoxin emitters, which he believed to be removing. Who's to say he DIDN'T add those deathtraps, believing he was removing them?
 * Except that the Lab Rat comic explicitly states that the facility didn't even have neurotoxin emitters until GLaDOS took over the facility, which is after Cave himself had passed away. The comic explicitly shows that it was GLaDOS who had these installed For Science!. Ergo, crazy as he was, Cave Johnson had absolutely nothing to do with the neurotoxin in the newer facility.
 * The comic doesn't "explicitly state" any of what you said. GLaDOS said she needed "a little neurotoxin", but nowhere does the comic say that they didn't already have neurotoxin generators or emitters. I always took her statement to mean that she needed access to some neurotoxin, or that she needed to be able to generate neurotoxin, not that she needed the equipment installed.


 * Why are the oldest parts of the lab the furthest underground? If you are building an underground facility, wouldn't you dig down when you needed more space, thus putting the newer parts the furthest down? Even ignoring the fact that keeping large testing areas that are no longer in use around instead of repurposing the space doesn't make any sense, why did aperture science build the first labs so deep underground and then move up?
 * The facility is built into an old salt mine and cave system, which existed before the lab. So the first testing areas were built at the bottom and newer facilities slapped upon the old ones, right up to the surface. That's why you end up in the oldest part after the long fall in the sequel.

Wet platforms

 * Something that's bugged me for a little bit: given that you die instantly the moment you touch the "water" and there are signs telling you not to drink it (why Aperture Science thinks their test subjects would want to drink water off a floor is something of a mystery, but anyways), this troper has always assumed it was some kind of corrosive acid. But when you jump onto the platforms in chamber 14 (the one with the complimentary victory lift), the platforms that have been submerged in this acid stuff, the soles of your bare feet are fine. No pain whatsoever. Do the platforms just dry off really fast? Is it something with the heel springs? What is the "water" anyways?
 * Small quantities shouldn't be a problem. And that's assuming the "acid" is killing you and not, say, your ASHPD shorting out.
 * Which makes sense considering she warns you about submerging it just after you get it.
 * There are some materials, like certain metal alloys, that are resistant to acidic corrosion. The platforms could be made of something like that.
 * Metal alloys? Plastics are more practical.
 * Or, the "water" did damage Chell's feet, albeit slowly. That's why in the second game you switch to the Long Fall boots, which must double as prosthetics.
 * Uh... at the risk of pointing out the obvious, you had the boots in the first game as well. They can be resistant to the liquid as well. By the way, who said that liquid was water. Looked pretty obviously corrosive to me.

Did GLaDOS plan everything?

 * Something that bugs me is the idea that GLaDOS planned everything out. The ending song doesn't seem to be a sincere declaration of everything going to her plan, it seemed more like a childish attempt to save face. "You think you won? Well, that's just what I wanted to happen anyways."
 * Yeah, why did that idea gain such a foothold? GLaDOS always struck me as, well, stupid. She's not even very good at pretending she doesn't want to kill you; it's like if SHODAN had a bad short and exchanged her god-complex for the mentality of a six-year-old.
 * Hell, the whole idea that this game has a plot more complex than "crazy computer makes you run through a death course for some reason" bugs me. What is it about this one game that leads people to massively overanalyse every line, piece of scenery and gameplay mechanic to come up with the story the developers were clearly trying to tell (which strangely never seems to have anything in common with what the next guy interprets it as)? Epileptic Trees even tend to include your character's ability to come back to life after dying and the fact that every obstacle can be passed, as if they were hugely significant to the amazingly subtle plot despite the fact that these two features are found in almost every game ever made.
 * The plot is quite sparse and mysterious and leaves plenty open to speculation, and for some reason it seems to have hit Critical Epileptic Tree Mass. After that, perhaps more people started overanalysing it just to join in the fun.
 * Where I come from sparse is the exact opposite of "deeper and more complex than 'computer puts you through death course for shits and giggles and spends the second half of the game taunting you just 'cause.'". Or maybe that's just me.
 * It's the idea that you really don't know what's going on that catches most people. Sure, there's some sort of computer who wants you dead for no apparent reason. And there's also several secret rooms where people write on the walls in blood and worship the inanimate objects in the room. And there's hints throughout the game that GLaDOS is not everything she appears, and connections to the Half Life universe, and why exactly did you wake up in a pod deep within a research facility? And why is that music so prolific through the whole game? Did the music drive the AI crazy? Where is everybody? What year is it? Who am I? WHAT IS GOING ON?! Soyeah...
 * So, yeah, "annoying" rather than "fun". Also, I have no idea what GLaDOS "seems to be" either.

Purpose of the portal gun

 * What exactly is the practical purpose for the portal gun? It doesn't seem like it would be very useful for stealthy entrances, since you have to physically get the gun within shooting range of the desired entry point before the portal will open.
 * ... it's a test device. Applying it for practical purposes is not the point. There are plenty of uses it could be applied for. Hell, since momentum is conserved through portals, and assuming no energy-drain due to that, you basically got a free energy device right there.
 * Shower curtain, duh. Make a portal into a shower with four walls and deactivate it, and you remove both the shower curtain effect and any leakage.
 * Dude, the question is what couldn't you use a portal gun for? You could use it to break into any building, scale any height, go anywhere in an instant, redirect projectiles, easily move heavy objects, drop your foes from incredible heights, and those are only the obvious uses. Sure, there are a few limitations, but technology marches on and it's only a matter of time before those limitations are eliminated.
 * We also now know that it can be used to  Which means that if the portal gun was successfully merchandised, anyone could  at any time, in seconds, and at next to no cost. Tell me how that would not be useful. Also, as shown in the very first scene in Portal, you can easily enter or leave a doorless room, as long as you have (and can control) one of those pieces of equipment that can create a portal on itself, and another one outside. You could make a room highly secure in this way, since you could make it as secure as a Panic Room without the vulnerability of a door. You could keep someone out or trap someone inside, and if they can't control the portals, they can't get in or out.
 * I still find it funny that the "perfect shower curtain" couldn't be waterproofed.
 * Retractable into a waterproofed box above the showerhead, or even build it into the walls (since we still don't exactly know how the first couple of portals were made, and the portals themselves don't seem to be weak against water). Assuming a healthy range of human buoyancy and a waterproof hair-trap detangler, or that GLaDOS is lying, it would be simple to design a shower to allow the Aperture Science Wall-Mounted Portal Device its full capability as a perfect shower curtain. Heck, if the portals are, in fact, waterproof, it would also be the perfect drain trap, since you could cover the floor with tiny portals and deactivate them, thus having both traction when active and a slick linoleum floor off of which to scrape the hair when inactive (since there would be no grate for the hair to stay tangled up around).
 * No need for that. GLaDOS can make portals in certain rooms without using the gun. That's how she gets you out of your cell.
 * Build guns that fire linked portals (remember, in the first stages of the game, the gun is two guns, only one of which is held by Chell). Put one in San Francisco and another in New York City. Fire each one at a wall. You've just killed the airline industry.
 * OR put one in New York...and the other one in a probe to Mars. Et Voila!Instant Planet Colonisation For Everybody!And lets don' start abou other stars...
 * Wouldn't opening a doorway into the vacuum of space in the middle of New York have....negative results?
 * Mars isn't a vaccuum, it has a thin carbon dioxide atmosphere. While leaving the portal open for extended periods might be harmeful to the earth in general, there would be no immediate negative effects.
 * Funny how you say that, Portal 2...
 * And perhaps the automobile industry. And elevator and escalator industries. And shipping industries.
 * Set up a Terminal Velocity portal pair in a tube, add turbines and water. Viola, place-anywhere limitless hydroelectric power.
 * Torture device. Put a portal above and below someone with them chained to the walls (so they don't fall through. Strip them down, and then leave them there, but feed them alot. If they have to go, they go on themselves. Lets say someone is afraid of mice. Put them in a room, put a portal on the ceiling, and then fill a room with mice. Then put a portal on the floor of that room. It's now raining mice. Someone is afraid of falling. Permafall until they talk.
 * For that matter, aversion therapy. Drop an acrophobic person through a low portal. When they're comfortable with that, drop them from the portal into another low portal. When they are comfortable with that, give them a vomit suppressant and drop them through a looped portal, then wait until they stop screaming and drop them into a thick foam room to be declared cured, calmed out of the catatonia (if possible) and put into round two, or calmed out of the catatonia (if possible) and sent home.
 * Or just kill them from shock or a heart attack. Was that your attempt at GLaDOS-esque humour?
 * The "until they stop screaming" and "calmed out of the catatonia" parts were (although not intended to be GLaDOS-esque in particular). Everything else was perfectly sincere, since aversion therapy is (usually) completely voluntary.
 * Those uses are all trivial compared to that Penny Arcade shirt.
 * ...which, assuming that's a full-grown adult, looks incredibly painful.
 * Um, how would that be painful?
 * Portal 2 reveals . Obviously you don't need to be that close.

Is Aperture undergroud?

 * The main entry states that the Aperture Science labs are an Elaborate Underground Base, but is there any evidence that it's underground? The website does not count considering who provides the info.
 * Sounds like a good thing to bring up on the discussion page of the main entry. Now... What bugs you?
 * Simple: Chell ends up on the surface - above GLaDOS' chamber. To reach that chamber, you have to cover quite some vertical distance upwards.
 * With portal 2 out, it's made very, very, very, clear that this lab runs deep below the Earth's surface.

The boss fight and biology

 * The final battle doesn't keep to the rules of human biology. If you were being gassed with a fast-acting poison that kills you in EXACTLY six minutes, you'd start to stumble, get dizzy, and have shortness of breath (at the very least) probably by minute 2 or so. This does not happen in the battle. Moving around is just as easy at the very beginning of the battle as it is toward the end.
 * No, I thought the poison wasn't actually released until the end of the six minutes.
 * But if I remember correctly, there's a gas coming out of the neurotoxin emitters during the entire battle.
 * GLaDOS starts emitting the neurotoxin immediately (the stuff you see), but then says she hasn't got enough to kill you, and starts making more - this takes six minutes. Presumably, you don't actually breathe any of the very little neurotoxin that's actually emitted. After the six minutes, the whole room is filled with neurotoxin, and you die very quickly.
 * Er, NO. The neurotoxin can be seen being released throughout the whole battle.
 * Maybe the neurotoxin emitters were just full of dust from being idle so long, and GLaDOS just needed to purge the vents of the conveniently green-coloured dust while the neurotoxin was being made.
 * Since the update showed that destroying GLaDOS was somehow related to the test itself, it's possible that it was just fake colored gas for the first 6 minutes and then when you "fail," she releases the real stuff and you drop dead.
 * There's some Dummied Out dialogue from GLaDOS about how the neurotoxin emitters are actually empty/she has to make more/there's not enough to fill the room, etc.
 * She has to WARM UP the neurotoxin emitters.
 * Agreed, this occurred to me too at some point. If they were making a movie they would have Chell react realistically to the neurotoxin, because it would make the scene way more tense and dramatic ("Holy crap she can barely move, oh c'mon the Anger Sphere is only inches away from the incinerator! AAHHH there's only 10 seconds left!! YOU CAN DO IT CHELL!!"). But Portal is a game, not real life or a film. You wouldn't be able to defeat GLaDOS if the neurotoxin affected Chell the way it affects people in real life. You'd be vomiting, crapping yourself, your eyes would be watering constantly, and at some point you'd be incapable of movement and would lose consciousness and go into convulsions. I repeat: It's a game. There are a LOT of unrealistic depictions of how things would affect Chell's body. For example, while the heel-springs stopped the testers' complaints that she wasn't sustaining damage from falls, in real life they wouldn't be anywhere near sufficient protection. Another example is that Chell is often launched great distances through portals, and just HAPPENS to always land on her feet (gravity pays her the rare courtesy of always reorienting her so that her feet are pointing down and her head pointing up if she passes through a portal feet-first), while in reality she could end up landing on her shoulder, on her back, on her sides, on her head, and seriously injure herself. Or she could miss her target and collide painfully with something. She has zero protective gear, she's not even wearing anything on her feet. And yet another example is that unless you're super-amazing at this game, Chell gets shot several times by turrets, and yet doesn't bleed to death and is still able to complete the rest of the chambers despite the massive pain the bullet wounds should be causing. Then when she's escaping the fire pit, she definitely comes close enough to the flames to suffer some burns, or at least have her clothes catch fire. Plus in real life someone doing these tests might conceivably take way longer than the game takes, and in that time would need to eat, drink, and go to the bathroom. Then there's all the crap she's exposed to in Portal 2, which I could make a list of, but won't because this bullet point is long enough. When you're designing a game you really don't have the option of having the player be realistic biologically.
 * "We asked this test subject to try and land on her head. See? She can't do it. Good work, boots!"
 * The boots aren't used in the first game, and the boots still wouldn't be able to stop her from colliding with things, or from landing on her head or side if there wasn't enough room for her to land on her feet.
 * There's at least 2 different tropes which apply to this. They are called Exact Time to Failure and Critical Existence Failure You would do well to get used to them. The second one, at any rate, is pretty well ubiquitous in video games, and the first one is a good dramatic tool. That's all there is to it.
 * If the neurotoxin is lighter than air then it must fill the whole room before it will kill Chell. That could take exactly 6 minutes.

Required "complimentary" lift

 * How can the victory lift in Chamber 14 be 'complimentary'? It's necessary to reach the exit.
 * You do realize that it's GLaDOS you're talking about? Haven't you noticed all her other weird lines up until that point? It's purely for humor purposes.
 * Chamber 14 actually has a shortcut, which makes the lift unnecessary. You deserve something for putting in all that effort going the long way, so you get a complimentary victory lift.

Making portals

 * What's really been bugging me is: what makes the portals? What kind of energy would that take? GLaDOS mentions something about "gamma-leaking portal technology", but gamma-rays are made up of waves and can't be captured in a container because they've got such a high frequency that they pass through everything. Is it some kind of cathode ray or radioactive/nuclear isotope maybe? I'm no scientist or engineer, so does anyone want to take a shot at some crackpot theories? Also, how does the portal gun get modified in chamber 11? I mean picking up another gun works for gameplay mechanics, but to make it into a plausible story is hard. My idea is that the gun in chamber 11 is some kind of dummy, and the test subject takes whatever generates the orange portals out of the dummy and puts it in the real gun. More crackpot theories?
 * It's a technology that rips a hole in spatial physics. Do you expect a complex and scientifically accurate explanation of how that would work?
 * I assumed that the portal gun doesn't actually make new portals every time it's used, it instead somehow stores two connected portals inside of it that it can "paint" on certain surfaces. A significant amount of energy was used initially to make the portals, but much less is is used to maintain/contain them.
 * Cave Johnson has all the answers: Moonrocks. That is all.
 * The Boots video shows the schematics of the portal gun. Basically? Dye and a mini black hole.
 * Quantum Entanglement the girls and boys at Aperture accidentally cracked open the secret to using Quantum Teleportation with classical information

Portals in portals

 * So, I just found this comic, and although it's meant to be Insane Troll Logic it actually made me wonder....what would happen if you did that?
 * Congratulations, you just broke my brain.
 * Wait a minute. Portals cannot go on moving surfaces...
 * Well.. Portal 2 suggests that there are scenarios in which it is possible.
 * At first I thought the portal would just stay in place and that the box would move without it, but then I remembered that the Earth is in motion, and the portals seem to move along with it.
 * Easy. The portals are the same size. Therefore the box for the blue portal would be larger than the orange portal. Therefore it wouldn't fit. Now, think about what would happen if you only put a corner through.
 * Instead of a box, use a flat panel like on the walls. The portals are taller than wide, so shift the panel sideways and move it through the other portal.
 * Well, obviously, the blue portal would come out of itself, with a blue portal coming out of it, and a blue portal coming out of that one, etc. This would instantaneously generate infinite mass and create a black hole. So please don't do that.
 * Except the blue portal would never get to the point where the part of itself which it is coming out of goes into the orange portal (thus making the blue portal be coming out of itself more than once--it would really be easier to explain this with a diagram). So it would not violate conservation of mass, it would just look really freakin' weird.
 * Watch the end of Farscape: The Peacekeeper Wars, tells you EXACTLY what happens when you stick one end in the other.
 * Alternatiely, you could ask Problem Sleuth

Proximity of test chambers to each other

 * Shortly after you escape at the end of Test Chamber 19, you encounter two observation offices from which you can apparently see Test Chamber 14 and Test Chamber 9. In fact, shortly after this you end up in TC9 for the second time in the game and must escape it through the elevator shaft. One problem with this: You are at this point nowhere near TC9 or TC14 (and TC14 is not close to TC9 either). The vertical separation is the most obvious: the elevator at the end of each TC takes you up and in general the exit of a test chamber is higher than its entrance (TC18 being the most Egregious example). By the time you escape from TC19 you are many, many, MANY storeys above TC9. The whole thing is impossible, unless M. C. Escher was a consultant in the design of the Enrichment Center. Though come to think of it, this is Aperture Science we're talking about...
 * Now you're not thinking with portals.
 * Level design doesn't always correspond to actual architecture, especially over multiple level transitions. If this doesn't satisfy you, there may well be multiple identical Test Chambers, or the Center restructuring system (seen in Portal 2) did it.
 * Remember the part after Test Chamber 19 when you jump down an elevator shaft? The shaft ended after one floor, with a portal-able surface on it. Your elevator itself travels via portals.
 * Portal 2 suggests the elevators work similarly to the Vital Apparatus Vents through the use of Pneumatic Diversity Vents. Just because they go up at both ends doesn't mean most of the distance isn't travelled in circular loops throughout the entire facility.
 * As mentioned a few points up, Portal 2 shows that almost any and all elements of the facility can be moved and changed at the drop of the hat. So there's really no problem here, if you're willing to retcon that feature into the first game even though it's never shown there.
 * This troper assumed the elevaors moved on the X,Y, and Z axis, not just up and down.

Hearing G La DOS in the second half

 * Why can you hear the computer voice in the back area after the test chamber portion is over? Are we supposed to believe they installed speakers back there?
 * Did you miss the bit where you passed the actual speakers in the back area? (Or am I wrong. It has been years since I played the game.)
 * There are intercoms placed throughout the back areas. GLaDOS is talking through those.

Spatial nausea

 * Does jumping through portals make anyone else dizzy? I was able to play the first hour or so of the game without incident, but because the later levels are pretty much nothing but jumping through a portal, catapulting yourself across the room, spinning around really fast, then jumping back through the portal you just made, I can only play for ten, fifteen minutes at a time. It's driving me crazy, but I know I can't really fix this, so just wondering if anybody else had this issue.
 * Are you female, or an older male? They both seem a bit more susceptible to that sort of thing.
 * Female. It's extra aggravating because I have never, ever had motion sickness before.
 * Ah. Bad luck then. It's just some spatial awareness... thingy. Women and older men tend to get motion sickness in FPS games, just one of those things. Try changing your FOV in the settings menu. It might help.
 * You're not alone. I'm female too, and the whole game including that out-of-focus shot of a chamber before the start menu pops up makes my head spin. Doesn't stop me from playing, but still. It's really irritating, I've never experienced such problems before.
 * On the other hand, this female player is usually quite fine (until she watches speedrun of this game, but that's a whole other ballpark). What bugs me is how I can be all right with Portal, but Super Mario Galaxy plays ping-pong with my brain.
 * Same here, I'm female and I was fine with Portal 2. Portal One made me a little nauseous, though.
 * I'm male and also feel dizzy after some time playing. Not much to do but stop playing every half hour or so.
 * Sorry to be the odd one out, but I've never felt dizzy playing either of the Portal games. *shrug*
 * What you guys are experiencing is a phenomenon fairly new in the video game experience. When you're playing a First Person game, you're flying around, and you can see your arms and feet, a game can actually hack into your PROPRIOCEPTION, or sense of self. What the game does is take your consciousness and actually convince you that Chell's arms and legs are your arms and legs. When you're careening haphazardly through the air, you body is completely and utterly convinced that you are careening haphazardly through the air - but your inner ear (your organ of balance) tells you that you are sitting perfectly still. When these parts of your brain are sending two completely different signals, the result is nausea. It's actually the exact inverse of seasickness or carsickness: your inner ear tells you you're moving, but your surroundings are staying still. The result is the same, however: nausea.
 * This hacking of proprioception is actually extremely common for players of the game Mirror's Edge, another First Person game in which you fly through the air and can see your arms and legs. It doesn't help that both Portal and Mirror's Edge also come with a bamboozling barrage of bright colors in an otherwise monochromatic setting, adding to your disorientation.

Companion Cube surviving incineration

 * When you're about to receive your complimentary burning, GLaDOS assures you that the Portal Gun will be unharmed because all Aperture Science equipment can withstand over 4000 degrees kelvin. So... my Companion Cube is still alive? ♥
 * Yes, yes it does. Relatedly, as you're going down there you can see and hear a radio playing music. What exactly is the point of making a radio that still works at 4000 K? I mean really, were they planning on trying to make a way to play music ON THE SUN? Coincidentally, this is why I decided to edit this page. A radio that's still operational at 4000 K just bugs me.
 * Disregarding the above spoiler, one could assume that the Aperture Science Emergency Incinerators are designed to destroy Aperture Equipment, and thus, that they are heated to more than 4000 degrees K. They have to have some way to destroy faulty equipment.
 * Emancipation Grids.
 * Emancipation Grids.

No alarms

 * Did anyone else notice that there weren't any alarms or sirens when a test subject left the foreseen test chambers, carrying a highly experimental time-space-bending-phyics-defying etc. device?
 * Er, why does this bug you? Why would there be any alarms or sirens? It's a maintenance area. I doubt they foresaw the need to automatically detect the presence of a person or portal gun in that area, and there aren't any people there to set off alarms manually (which is probably how it would have been done if it was ever done at all).
 * Additionally, there is a Dummied Out line where GLaDOS says, "The device will detonate if removed from an approved testing area". Either she was lying or the device was faulty, but perhaps the Aperture Science employees said this to test subjects to deter them and that was enough security for them? This is Aperture Science, after all... I mean, in Portal 2, in the old testing spheres, they apparently allowed test subjects to use the old portal device when doing so could have wiped out time. If they didn't have a problem with possibly wiping out time, I doubt there's much of anything they'd have a problem with...except lemons.
 * There probably are alarms, but there's no reason to tell the test subject that they've been activated. G La DOS is obviously watching all the test areas all of the time, and has limited knowledge of what's happening behind the scenes. She knows enough to turn on pistons, activate rocket launchers and drop turrets.

Where the Rat Man goes to the bathroom

 * We've all seen the Aperture Science cans of beans and milk Rat Man was living off of, but...where does he poop?!
 * He uses the toilet in Chell's relaxation chamber, obviously.
 * Also, where is he storing the milk so that it doesn't go bad?
 * He isn't.

Firing the whole bullet

 * I know, Rule of Funny.. but why bother loading up the turrets with the entire bullet? Assuming it's some kind of magnetic/railgun type, why not just pack in more actual bullets (as in the bullet itself, not the entire round). Although I suppose someone getting an entire 5.56 or 7.62 bullet in the face or chest would do some damage.
 * Because he's Cave Johnson, and he's not going to settle for conventional when the wildly improbable can be done.
 * In fact, one of his science types probably tried to explain this to him, and you know what Cave likely did? Fire his egg-head ass and hired someone to do what he says without question, and more asbestos!
 * It's 65% more bullet per bullet. You can't get that kind of increase per bullet without shooting more bullet.
 * More mass=more impact force=better chance at a kill shot.

What G La DOS tests

 * What exactly is GLaDOS testing? What sort of science needs a human to solve puzzle rooms?
 * She really isn't testing. She's just playing puppet master and toying with test subjects for amusement before killing them. Also she stated that her body emits a euphoric sensation every time a test is completed, but over time she has grown immune to the feeling. So she sort of became driven mad from her addiction to fun times with science.
 * I don't think so. Why does her body emit that euphoric sensation? Because the folks at Aperture built her that way. Why did they build her that way? Because they wanted her to run those tests (see also the electric shocks intended to discourage her from interfering; she was only supposed to supervise the tests). You know, the same kind of tests they've been running since the 50's, long before GLaDOS was built. The same kind of tests Cave Johnson paid homeless people to run through at one point in history. So why did the folks at Aperture run these tests? What was their point?
 * At one point in Portal 2, GLaDOS explains that it didn't matter to her that she became immune to the euphoria because she "was in it for the science".
 * She doesn't say that. She says that developing a resistance to testing euphoria didn't matter to her because she was in it for the science. To put it another way, the testing itself was her reward; the euphoria was just a nice extra.
 * Why would we trust GLaDOS on this point?
 * Because she's a potato, and coming to terms with Caroline.
 * It's Cave Johnson. He doesn't really need a point, just the idea is enough. He may very well have strapped a toaster to those homeless peoples' backs, told them to run through a room made of sawblades, and called whatever came out the other end "science".
 * Hmmmm, I knew there was something I forgot to get the lab boys back to working on. Remember folks, if there's an idea, We have the funding to do it . . . for Science!
 * The tests were originally for two purposes: Evaluating the tactical unity of the portal gun, and finding people who were good with it. Aperture used to get a lot of military funding, or so I've gathered.

Portal malfunction at the end

 * Why does destroying the fourth core cause GLaDOS to have a gravity-reversing catastrophic episode, anyway?
 * Simple - The first core was a limiting core to keep her not murdering people, and the rest were actually part of her, and required for her to function correctly. In Portal 2, she's brought back online without them, and is clearly insane.
 * She was clearly insane to begin with. And actually, what happens is a portal malfunction, which G La DOS's destruction doesn't explain.

The Rat Man was never promised cake

 * Why does Rattman write "the cake is a lie!"? He was never a test subject, so he was never promised cake in the first place.
 * Actually, he was a test subject. After gassing most of the facility, GLaDOS ran any survivors through the test chambers to satisfy her inbuilt desire to supervise the Enrichment Centre. Before the neurotoxin incident Aperture had been using its employees as lab rats anyway, so it's not out of the question for poor Doug to be familiar with her, uh, motivational methods.

The Heimlich Counter-Maneuver

 * Now, I understand that it's Cave Johnson we're talking about here, but... the Heimlich-Counter Maneuver. Ignoring the inherent lunacy of it, how is it that he expects it to get money from it? Does he expect to collect a royalty for every time someone performs it (which would, hopefully, be few, if any) or off posters or something?
 * He was slightly more insane than usual when he thought it up. Making someone choke and at the same time countering the heimlich manuevre was done by the military using these techniques though, so it is a pretty potent weapon.
 * And since you mention it, the military probably did pay him for it.
 * It'd probably be useful for assassination, so if you have certified instructors, you can teach a course in how to do it. For a small fee and signing a confidentiality agreement, of course.

From shooting one portal to two

 * When you get the second gun that lets you shoot both portals, what exactly is it? Is it a mod for the original portal gun ("the device has been modified" according to GLaDOS), or is it an entirely new gun, and if so, what happens to the old one?
 * Gameplay and Story Segregation. The second is likely used to modify the first in some manner, you just don't see the discarded shell.
 * I imagine that, story-wise, it is a mod designed to be easily connected to the device, in a kinda Plug-n-Play, "just slide it onto the rail and push until you hear a click" way. GLaDOS's line suggests that it's just an expansion device for the ASHPD, and it would have to be easy to assemble, since you can't expect the test subjects to be familiar with the gun's construction. Also, the completed device is more valuable than the organs and combined income of everyone in, so I doubt they would've built more than one for the testing unless it was absolutely necessary.
 * It seems that there are multiple portal guns; some which fire one portal and some which fire two, as shown in Portal 2. It's possible that the second one could fire both, but was just firing orange portals; however, I'm not sure how the portals from the first gun would connect to the second and vice-versa or what happened to the first gun after Chell collects the second.

Pressing buttons

 * Overweight jokes aside, why can Chell press buttons by standing on them but not by placing turrets on them, even though, presumably, a turret would weigh more than a human?
 * Because it turns out turrets don't weigh more than humans?
 * Maybe the button has an inbuilt sensor and can only be depressed by a human or Cube?
 * Those turrets aparently aren't part of tests. They're merely obstacles or guards. Maybe they don't count as "test helpers" like cubes or balls.
 * Most likely, the buttons react to weight and to electrical conductivity. Chell conducts well enough, the cubes conduct well enough, the turrets do not.

The Emotion Core levitating

 * How does the Emotion Core hang in mid-air in the final battle?
 * Maybe it found a way to harness it's pure unadulterated rage to give itself the ability to levitate?
 * Actually, GLaDOS used a sort of levitation or tractor beam to make it float. It's greenish and it can be seen carrying the core.
 * Then why she didn't use the same tractor beam to pull it back and plug it back in? Or at least move it around so you couldn't get it. Come to think of it, why didn't she do that for all the cores?
 * She was getting all glitchy and losing controls of her functions, like controlling the missile-launcher. She probably lost the control of the tractor beam too, so if she couldn't bring it back, she would make your life harder instead. It was a 5 minute battle, she didn't really expect Chell to be able to get it.

Want You Gone

 * "Goodbye my only friend . . . oh, did you think I meant you?" Wait, then who DID she mean?
 * The Companion Cube, duh. (Alternatively, she was teasing.)
 * G La DOS is being very Tsundere with that line. She DOES mean Chell, but she wouldn't state it out-right like that, and would immediately deny calling Chell her only friend.
 * "When I delete you maybe I'll stop feeling so [REDACTED]" Does she say "bad" or "G La D"???
 * It's "bad" -- turn on the subtitles and you see it.
 * Here's my thought: this entire verse is dedicated to Caroline. "Goodbye my only friend" was directed at Chell, but then Caroline thought that G La DOS was talking to her. "Oh, did you think I meant you?" was directed towards Caroline, along with the rest of the verse up until after "If I delete you maybe I'll stop feeling so bad."

Portal Placement

 * On what surfaces can portals not be placed? Has anyone found any strong consistency in this?
 * Maybe any surface without moon dust on it, since that's what the gel's supposed to be made from.
 * Aperture was testing portals before they knew about the properties of the moon rocks, so that can't be the only option. From an in-game perspective, it seems flat white or whitish surfaces support portals. This may not be as silly as it first seems; portals may depend on a material's ability to reflect certain wavelengths of radiation (i.e. light). Other details are a mystery. Density, electrical or thermal conductivity, or even quantum-level properties could have an effect.

The portal at the end of Portal 2

 * Has anyone ever noticed that, when you're going to shoot, both the portals being displayed are orange? I mean, if you look to the side, the orange portal is in the roof of the Stalemate Button room, and the other portal below is also orange, independent if it was orange before. I know it's because you really can't miss that one shot, but still, it's a little odd. The game designers could have made a game over screen, Torin's Passage's ending style.

GLaDOS' Insults

 * Why does G La DOS harp so on Chell's weight?
 * To make her feel bad. G La DOS is mean.

Wheatley's accent

 * Why does Wheatley, a robot built by an American lab ,by American scientists, in America (where all other robots talk with either American or "robotic" accent), have a British accent and vocabulary?
 * Because he's voiced by Stephen Merchant.
 * I know the Real Life reason,but what's the In-universe explansion
 * Because Aperture hired a british guy to voice him? It's not that uncommon if you want a varied group of voices, and they had a lot of personality spheres.
 * Sure, the robots all have American accents, but they're hardly uniform. Listen to the way the different spheres talk, and then compare it to the turrets/defective turrets. They're all from different regions and have their own distinctive flair.
 * One of the stated reasons that Valve hired Stephen Merchant was because he could speak very quickly and still be understood. Maybe that's enough to be the In-Universe reason as well.
 * Women love British accents, so GLaDOS would be less likely to just tune him out if he's got a British accent.
 * Probably because they felt like it. This is Aperture Science, after all.

The location of the final chamber.
When the roof of Weatley's chamber collapses, you can see the sky and the Moon through it. Apparently the chamber is on the surface or near it (the ceiling is high, sure, but not that high). Yet after Glados lets you go, you have to take a lift and go multiple floors up, and when you finally emerge, there are no structures on the ground. So, where was that chamber?
 * I guess the chamber is moveable, like most of the facility.
 * Any reason why Glados would suddenly move it many stores underground before releasing Chell? Besided, the final landscape doesn't look like any whatsoever large facility had ever been there.
 * Becuase she just saw a Test Subject defeating another A.I using the MOON? I think getting the place as far from the surfaceas she can is a pretty good idea

Time asleep
Why does everyone seem to think that Chell was in suspension for centuries, when the evidence we have from the first chapter, Courtesy Call, only suggests a few decades?
 * The amount of 9s said by the computer, though it is likely far less time.

Greg.
So, why do have Greg instead of Caroline in the Perpetual Testing Initiative? Is it just for the sake of the Development Gag, or was Ellen Mc Lain not available, or...?
 * More likely Cave just has more than one assistant.
 * Nobody said that Portal and Portal 2 happen on the same universe as the PTI's "Earth 1".
 * After pulling you out of Computer!Cave's universe,

Victory Candescence Room

 * I know the gameplay reason for this, but why was the firepit trap so easily escapable with portal-walls and a convenient ledge up ahead? In the second game, even . So, barring any interpretations that the firepit was part of the test, is it just sheer laziness on G La DOS' part or what?
 * Because it was unexpected. Most test subjects would just lay down and die in the face of danger like that, but Chell was different. Chell was never supposed to be tested(because she was such a Determinator) so G La DOS would never expect a test subject would even try to escape.