Portal 2



Portal 2 is a sequel to the game Portal, released on April 19, 2011. It picks up the story of Chell an unspecified number of years after the events of the first game. The Aperture Science Enrichment Center has fallen into ruin, and Chell is awakened from cryogenic sleep by Wheatley, a talkative Personality Core who needs her help to escape the lab. While roaming the remains of the facility, the two accidentally repower GLaDOS—who is, needless to say, not too happy to see Chell again. GLaDOS puts Chell right back into a series of test chambers while she works on getting the Enrichment Center to rebuild itself, while Wheatley continues to attempt to engineer an escape.

During the course of the game, much is revealed about Aperture Science's backstory—as well as the backstory of its founder, Cave Johnson, and several other characters. The game introduces new environments, including the ruins of the Enrichment Center from the first game, the abandoned facilities of the original Aperture Laboratories, and a haphazard and idiotic renovation of the modern test chambers. While the game is still fairly linear, it offers a lot more room for exploration and many puzzles involve getting from one test chamber to the next, not merely solving the challenges within.

The two-player cooperative mode deserves its own mention, as it isn't simply a retread of the main game; instead, it takes place in a different set of test chambers with a separate plot and fresh revelations about the world of Aperture Science. The playable characters are not humans, but instead a pair of robots named ATLAS and P-Body that were created by GLaDOS as "the perfect test subjects". (ATLAS' design is based on a Personality Core, while P-Body's is based on a turret.) The co-op mode ups the ante significantly in terms of the complexity of the puzzles, thanks chiefly to having two extra portals to work with.

New gameplay elements include Thermal Discouragement Beams; Hard Light platforms; Aerial Faith Plates that hurl you through the air; the Repulsion, Propulsion, and Conversion Gels; Excursion Funnels; and the myriad ways which the player can manipulate these new elements with objects and portals.

Unlike the first game, Portal 2 is a full-priced game, but the single-player campaign runs 2-3 times as long as in Portal, and the co-op is similarly paced.

A co-op and challenge DLC pack entitled "Peer Review" was released on October 4, 2011. The DLC allows players to perform a Speed Run in each map and compare their results against their friends' records. In co-op, a new group of test chambers are present to further challenge players and a new plot is introduced for it.

A second DLC pack entitled "The Perpetual Testing Initiative" was released on May 8, 2012. It allows players to design and share their own test chambers through a new creative mode built into the game. These player made chambers can then be used to play through a pseudo-single player campaign about Cave Johnson sending test subjects to explore (and steal from) Alternate Universe versions of Aperture Science. Instead of playing as Chell, the player character is one of the generic stick figures featured in the Cave Johnson trailers, officially named "Bendy."

"Space Prison warden!Cave Johnson: "Attention, test prisoners attempting to escape through the air ducts, I'd like to remind you that despite what the movies say, the air ducts go straight to the air conditioner. And it's pretty dusty up there, so if you have asthma you'll probably die. And we'll be smelling it for weeks, because, again, air ducts aren't some magical escape route, they're how we ventilate the facility.""
 * Accent Adaptation: At one point, Wheatley slows down his Motor Mouth and badly imitates an accent because he thinks GLaDOS cannot hear him that way. Each dub takes a parody of accent from an overseas country to the "origin" country: American in English, Argentinian in Spanish, Quebecois in French, Swiss in German. You can hear them all here!
 * Adorable Evil Minions: The sentry turrets.
 * Affably Evil:
 * A.I. Is a Crapshoot: Played with—the programming of GLaDOS' main body will apparently . Several safeguards were instated to prevent GLaDOS from getting out of hand, from mundane to downright ridiculous. Yeah, that didn't go too well.
 * Air Vent Passageway: In PeTI, an alternate universe Cave Johnson explains to his test subjects why this is a bad idea.
 * Air Vent Passageway: In PeTI, an alternate universe Cave Johnson explains to his test subjects why this is a bad idea.

"GLaDOS: (As P-Body and Atlas kill some turrets) (suddenly chipper)"
 * All Girls Like Ponies: Invoked by if you pass  and return after the trap is sprung to encourage Chell to jump into the pit, along with a series of other stereotypically "girly" incentives.
 * All That Glitters: Done sarcastically by GLaDOS at one point near the end of the Co-Op campaign. Where she claims that even though  the bots still have the trust they formed throughout the test.
 * All There in the Manual: The Lab Rat tie-in comic bridges the gap between the two games, as well as resolving the fate of the mysterious "Ratman" who scribbled on the walls. It also provides a lot of backstory, if you read between the lines, offering a possibility for where GLaDOS got the neurotoxin to begin with and explaining why Ratman drew cats on the walls in the sequel.
 * Alternate Reality Game: Continuing from the changes to Portal, on April Fools' Day 2011, the plot thickened with "PotatoFoolsDay", in which 13 indie games on Steam (the Potato Sack Pack, including Amnesia the Dark Descent, Audiosurf, BIT.TRIP BEAT, Defense Grid the Awakening, Killing Floor, Super Meat Boy and AaaaaAAaaaAAAaaAAAAaAAAAA!!! - A Reckless Disregard for Gravity) saw the in-game appearance of cryptic messages and/or graphics, eventually culminating in a hostile takeover of the games' universes by GLaDOS herself, using their powers to initiate a boot sequence. However, she required additional CPU power to do so. If players could generate that power by playing the games, the Steam release date would be bumped up. They succeeded in knocking off about ten hours from the original time.
 * Alternate Universe: The Excuse Plot for the PeTI DLC is that Aperture is nearly bankrupt, so to save on test chamber construction costs, they sneak the designs into an Aperture in an Alternate Universe, let them build it, then steal it back. In nearly every one of these alternate universes, Cave Johnson is still CEO/Prison Warden/Matriarch/Whatever of Aperture (except for one where it's Doug Rattman).
 * Aluminum Christmas Trees: Apparently, the moon rock poisoning Cave Johnson was afflicted with is a real hazard. Lunar dust is just as destructive to human lungs as asbestos, which means like Cave, you will suffer a slow, horrible death if you breathe too much of the stuff in. The effects are similar to silicosis, symptoms of which are displayed by Cave.
 * Always Someone Better: Cave Johnson ended up running Aperture into the ground in part because he wanted to out-do Black Mesa. Yes, that Black Mesa.
 * Hilariously, Cave bought out Black Mesa in an alternate universe. He proceeded to shut down the anomalous materials research division on the grounds that it might possibly cause a resonance cascade, chastising the scientists for their apparently lack of common sense.
 * Anachronism Stew:
 * The trailers narrated by Cave Johnson feature technology that would have been created long after Johnson had died in-universe.
 * In the test chambers from The Fifties, Johnson often refers to "astronauts" who have "flown into space". The first man in space, Yuri Gagarin, made his historic flight in 1961.
 * And I Must Scream:
 * Between games, GLaDOS' black box feature meant she spent years reliving the last two minutes of her life in which you killed her. Over. And over. And over. If the 300 years in the future thing is accurate, this means she relived that roughly 78.8 million times; no wonder she's pissed off.
 * Of course, all we have is GLaDOS's word on this, who we all know is a lying liar who lies.
 * GLaDOS also implies this is what she's planning to do with Chell (at first), running tests over and over until she dies, then reanimating her to do it again, forever.
 * also seems to qualify, what with being, but he's more upset about never seeing Chell again than his eternal exile.
 * And Now for Someone Completely Different: Single player mode has you playing as Chell while Co-Op has you play as one of the robots, Atlas and P-Body. Playing on a community map from the Steam Workshop DLC has you playing as neither Chell or the robots, but as one of the stick figures from the many videos seen in the game and by Valve. He has been officially dubbed as Bendy by Valve.
 * Anti-Frustration Features: The developer commentary mentions several occasions where they cheated in the player's favor to make some parts of the game less frustrating. Specifically, the game is extremely forgiving of entering portals while carrying objects, Propulsion Gel has a tethering effect that helps keep you running straight so that a minor trajectory error won't kill you, Repulsion Gel will automatically make you jump if you hit it at speed, many portal surfaces auto-center your shot, in the part of the game where conversion gel shoots through the vents and paints the walls you are surprisingly enabled to walk backwards up the wall to get to the top and proceed to the next part, and in two time-critical areas the game will switch portals around if you accidentally shoot a portal of the wrong color.
 * Ape Shall Never Kill Ape: Invoked and then cruelly subverted by GLaDOS.

"GLaDOS: You were right, Blue. Orange was dumb enough to fall for your trap."
 * Apple of Discord: GLaDOS does her best to find one during the co-op campaign, such as pretending to be in conversation with Blue/Orange about how awful Orange/Blue is or this, when one of the robots dies:


 * Arbitrary Maximum Range: Hilariously subverted . With the speed of light delay actually accounted for.
 * Arc Symbol: Potatoes.
 * Also (Schrödinger's) cats and the moon.
 * Greek Mythology involving Prometheus to a lesser extent.
 * Art Evolution: The Rat Man sure got a lot better at drawing on walls between games.
 * The developer's commentary notes that one reason they initially put players into the test chambers from the first game was to give them a chance to appreciate the graphical improvements against a familiar setting.
 * The elevators and Material Emancipation Grills look very different than they did in the first game. The Emancipation Grills were changed due to them looking "threatening" to playtesters who, ironically, kept walking through them without realizing their purpose until a puzzle appeared that utilizes them. The new design is meant to represent something along the lines of flowing water. Meanwhile, the elevators were redesigned to have large screens surrounding them, which play videos as a way of rewarding the player for completing the test.
 * Artificial Stupidity: Wheatley is an invocation of this trope..

""Let there be light. That's... uh... God. I was quoting God.""
 * Also a subversion as,.
 * Art Shift: "Bendy", the two-dimensional stick figure protagonist of the PeTI DLC. That's not an exaggeration. Using portals to look at yourself shows that he is completely flat.
 * Ascend to a Higher Plane of Existence: In the PeTI DLC, one of the parallel Caves has apparently turned the staff of Aperture and himself into beings of pure energy. He hopes one day to reach that Earth's ultimate goal of turning into giant pillars of salt.
 * Ascetic Aesthetic: The modern test chambers are in this style, when they're not overgrown or broken by Wheatley.
 * As the Good Book Says...: Wheatley does this after turning the lights on in the breaker room. It's also Foreshadowing.

"Announcer: Stalemate detected. cannot continue. GLaDOS: Wheatley (Currently plugged into a socket.): Pull me out! Pull me out! Pull me out! Pull me out! Pull me out! Pull me out! Announcer: (Speaking over Wheatley.) ... unless a Stalemate Resolution Associate is present to press the Stalemate Resolution Button. Wheatley: Leave me in! Leave me in!"
 * Astronomy Goof:
 * Attack! Attack! Retreat! Retreat!: This little exchange:


 * Given a reprise of sorts later:

"GLaDOS: *to P-Body and Atlas* Go get her! They enter a large room GLaDOS: Oh my god! Run! Forget your training! Abort! Abort!"
 * At the end of Peer Review

"Announcer: Reactor explosion timer destroyed. Reactor Explosion Uncertainty Emergency Preemption Protocol activated. This facility will self-destruct in two minutes."
 * Aw, Look -- They Really Do Love Each Other:
 * Back from the Dead: GLaDOS, of course. (Also, apparently ).
 * Bad Boss: Cave Johnson is suggested to be a spectacularly bad one of these even before he resorted to testing on his employees and their families. He does seem to have a soft spot for his secretary Caroline, although even that gets twisted around toward the end of his life.
 * Bad Liar: GLaDOS of course, but she has improved a bit from the first game. Wheatley even more so, and it gets worse as the game progresses.
 * Baleful Polymorph: Non-magical version. Also comes with a Brick Joke, see below.
 * Berserk Button: Wheatley really does not like to be called a moron.
 * Better to Die Than Be Killed: During the endgame boss battle, one of the ancillary functions that gets damaged is the countdown clock to nuclear annihilation. In order to remove the uncertainty this generates in the Exact Time to Failure, the computer backup systems preempt the countdown with a second countdown after which the facility will self destruct on its own. The folks at Aperture Science are extremely efficient.

"Wheatley: (to self) Hmm... could be Spanish, could be Spanish... (to Chell) Hola, amigo! Abre la puerta! Donde esta--no, um..."
 * Shortly before the Final Boss fight, you're offered a chance to kill yourself rather than be killed, because then your death will be "voluntary". And very much appreciated.
 * Big Door: The door to the old Aperture Science facility. The developers found this a highlighting feature of the game, having "the biggest door in video games!" Behind it is
 * Big No: From GLaDOS of all people.
 * Big "Shut Up!": Wheatley does this to the automated announcer when it mentions that.
 * Bilingual Bonus: At one point, Wheatley attempts to show off by speaking Spanish through a translation program without knowing what he's saying. The Spanish translates to "You are using the translation software incorrectly. Please consult the manual." In the Spanish version of the game, Wheatley says that line in English: "It seems that you are using the translation tool incorrectly. Please check the manual."
 * Also in the beginning of the game, if you wait long enough to open the door to the Relaxation Chamber, Wheatley will speak in Spanish.
 * Also in the beginning of the game, if you wait long enough to open the door to the Relaxation Chamber, Wheatley will speak in Spanish.

"Cave Johnson: Don't have any tumors? Well, if you sat on one of the chairs in the lobby and weren't wearing lead underpants, we took care of that too."
 * In the "Lab Rat" comic, Chell's profile includes five lines of binary near the bottom. When translated, they read "The cake is a lie."
 * Bindle Stick: Referenced by Cave Johnson in the 70's era test chambers.
 * Black Comedy: So, so much. See the Funny page for examples.
 * Blatant Lies:
 * "Asbestos is harmless!"™
 * Everything says when trying to convince   to jump into the pit.
 * And GLaDOS bears no ill-will towards Chell for how the events of the first game turned out. None whatsoever.
 * Bloodless Carnage: Unlike in the first game, there are no signs of blood at all, to keep the rating at E10+. Taking damage just gives your screen a reddish tinge.
 * Blown Across the Room: Used for dramatic effect during the Final Boss fight. Also, Chell during the beginning, every time Wheatley crashes into the docking bay door.
 * Body Horror
 * In a Call Back to the first game, the announcer mentions that the Material Emancipation Grill may occasionally "emancipate the ear tubes inside your head".
 * A rare robotic example with the Frankenturret in Chapter 8; literally the front part of two sentry turrets merged crudely to the back of a weighted cube. The way it struggles to move is like watching a crab hop around without its hind legs. The worst part is that you can tell it's in pain. They're also at least intelligent enough to be fried by a Logic Bomb, meaning that, sadly, they're.
 * Pretty much anything Cave says in the recordings when you're in the old facility. Things along the lines of a possibility of your body being filled with tumors; coughing up (or shitting?) coal, your bodily fluids being turned to gasoline, being teleported without your skin, and opting to have scientists 'disassemble' your body, take out your tumors, and reassemble you.

"GLaDOS:"
 * Booby Trap:.
 * Book Ends: Early in the game as Wheatley pops off the rail, he yells "catchmecatchmecatchme!" and at the end,
 * Wheatley wakes you up in the first place to get away from the destruction of the facility due to a reactor meltdown.
 * The song that plays when you first meet Wheatley
 * Bolivian Army Ending: Subverted.
 * Boss Arena Idiocy: Played with extensively across both boss battles.
 * Averted with GLaDOS, who has learned from her mistakes in the first game.

""Oh, that just cleans right off, does it? Well, that would have been good to know. A little earlier.""
 * Justified, as the mainframe area appears to have certain features that the controlling AI cannot simply remove or disable, including the Stalemate Resolution Annex and the replacement core receptacle.
 * Defied by, who studies GLaDOS' previous loss to Chell and sets the arena up specifically to avoid her mistakes. Naturally, being  proceeds to zig-zag it with a whole new slew of glaringly obvious mistakes:
 * Played straight when forgets about the clear glass tube of Conversion Gel running through the arena, as well as the non-clear but still breakable tubes of Repulsion and Propulsion Gel, and Lampshaded after the fight.

"Wheatley: Let's try it her way. Fatty. Adopted fatty. Fatty-fatty-no-parents."
 * Subverted, as anticipates the possibility of losing the fight and
 * Double subverted, as refusal to acknowledge the ongoing collapse of the Enrichment Center is what opens up the vulnerability that allows Chell to finally win.
 * Boss Banter: Taken to new heights, from GLaDOS' renewed snarking to
 * Bottomless Pits: This game features them and not even boots can save the portal device from breaking when falling into these.
 * Brain Uploading: Cave Johnson instructed his scientists to work on uploading technology after he became fatally ill from moon rock poisoning. He left instructions that if he died before it was ready, it should be used on
 * One of the alternate universe Caves actually did succeed in uploading himself. He quickly went (more) insane and decided to "kill" Aperture. Cave Prime pulls you out of that universe, and resolves to.
 * Bread, Eggs, Milk, Squick: A wall sign in the old labs invites you to "KNOW YOUR ALLERGENS: Pollen. Animal dander. Plastics. Antimatter".
 * Breaking the Fourth Wall: A meta example during the ARG, where GLaDOS literally invaded a bunch of Steam-based applications and made Portal-themed changes to them, such as turning items into Companion Cubes, and replacing their soundtracks with Portal-themed tunes.
 * Break the Haughty:  Being forced to work with Chell as a result sets the stage for some significant Character Development.
 * Briar Patching: The Final Boss is telling you the truth about how you shouldn't . What it doesn't say is that . And it is a fairly obvious one, at that, but, as in the first game, Stupidity Is the Only Option.
 * Brick Joke:
 * In an early test chamber, the recorded messages mention that the Aperture Science Personality Cores can remain operational with power as low as 1.1 volts. Later
 * Early on in the game, Wheatley mentions that he jammed up the door mechanism by dropping some bird eggs on it, and freaks out when the bird in question starts flapping around him.
 * One of the possible apocalypse scenarios is "The world being taken over by an animal king", illustrated by a giant leopard-skinned turret with a golden crown..
 * In the first game, GLaDOS makes the comment that "all Aperture technologies remain safely operation in temperatures up to 4000 degrees Kelvin." At the end of Portal 2,
 * Just after the first hard-light bridge test, the elevator you need to take at the end of a level has a large, fat turret sitting in it, which speeds off as soon as you see it.
 * Wheatley offhandedly mentions a part of the facility that contains robots that scream for absolutely no reason, framing it as a ghost story. Fast forward to right near the end of the game, where
 * The turret you can save from the redemption line is the same one Wheatley awkwardly ignores and tells you not to make eye contact with at the beginning.
 * Late in the game, tries to kill you with the same defective turrets you used against GLaDOS much earlier.
 * An interview with Eric Wolpaw revealed that Cave Johnson's line about missing astronauts would have led to
 * At the end of the Peer Review DLC, the scarily competent individual GLaDOS has been preparing you to kill turns out to be.
 * One of the parallel Universes in the level-creator DLC is ruled by a sentient cloud, as the Announcer mentions in the start of the main game.
 * One of the Caves is also a mantis, injecting people with human DNA.
 * Broken Record: The Space Core. He likes to talk about space.  A lot.
 * Buffy-Speak:

"Cave Johnson: Space-criminals, political prisoners, exiled planetary leaders; you're here because the galaxy needed a place to put you, and this is it. So, who's ready to stay here until they die? I assume you already met each other on the hyperdrive over..."
 * But Thou Must!: You can't do anything but press the Stalemate Resolution Button. Both times. Whether you think it's a good idea or not. Similarly, you have no choice but to rescue, and even if you cleverly make it to the next level anyway, the game assumes you did.
 * Call a Rabbit a Smeerp: In the co-op campaign, some chambers use an Edgeless Safety Cube instead of cubes. Guess what it looks like:.
 * Call Back: Oh, so many.
 * It's slightly jarring to walk into a test chamber that you played in the first game and find it completely in disarray. At one point you navigate the old Test Chamber 19 backwards, crawling out of the ruined Victory Candescence room and through a trench that used to be a moat of toxic goo.
 * In one of GLaDOS' "new" test chambers, you catch a brief glimpse of the Aperture Science High-Energy Pellet device before it's replaced with a Thermal Discouragement Beam emitter.
 * The poor faithful Weighted Companion Cube makes several appearances.
 * May also count as a song Title Drop:
 * In the first game, GLaDOS says "DO touch it." after the Morality Core pops out of her and she tells Chell not to touch it because she doesn't know what it is.
 * At the beginning of the game, after you've fallen and obtained the Blue Portal Gun, Wheatley asks something along the lines of "Are you alive? That's important, should've asked that first. Right, well I'm going to work under the assumption that you're still alive..."
 * When Wheatley is trying to hack into the neurotoxin controls, he says "Let the games begin."
 * When you escape the  starts trying to convince you to come back in a very similar manner to GLaDOS from the original Portal, when you escaped the fire pit.
 * One of the bits of garbage GLaDOS hurls at you is one of the old radios, playing the exact same version of "Still Alive" as the radios in the first Portal.
 * The door you open to  says "GLaDOS EMERGENCY SHUTDOWN AND CAKE DISPENSARY". This is also the only reference to cake in the entire game.
 * You get the dual portal device from the bottom of the fire pit where GLaDOS tried to kill you in the first game. Assuming that not all test subjects were as Genre Savvy as Chell, it seems the portal gun really can survive temperatures of up to 4000 degrees Kelvin.
 * One of the parallel Cave Johnsons does a reworked version of his introductory speech in the level-creator DLC, in a universe where Aperture's a prison for intergalactic criminals.
 * One of the parallel Cave Johnsons does a reworked version of his introductory speech in the level-creator DLC, in a universe where Aperture's a prison for intergalactic criminals.

"Cave Johnson: Black Mesa can eat my bankrupt-- Caroline: Sir, the testing?"
 * The Cameo: Atlas and P-Body make a brief appearance at the end of the single-player campaign. Before that, P-Body can be seen in one of
 * Captain Obvious: Wheatley.
 * The Cast Showoff: Ellen McLain actually sings opera this time. In Italian. To lyrics she made up herself.
 * Though Coulton wrote "Still Alive" ahead of time, he was able to write "Want You Gone" with her in mind, allowing her to give a richer, fuller performance.
 * There's also this song, one of the game's best kept secrets, which has been given the official Fan Nickname of . It's in Latin this time, with McLain coming up with the lyrics again (according to what she calls her "bad high-school Latin", resulting in Word Salad Lyrics), though they're heavily garbled. Proves that she could sing complete gibberish and it would still be hauntingly beautiful.
 * Chaos Architecture: The Aperture Science Enrichment Center houses manufacturing facilities to build a variety of walls and standardized objects, arrays of articulation points to form those into test chambers, and a vast rail system to move those test chambers about the facility. This results in a maze of shifting test chambers. Even damaged test chambers can be rebuilt and replaced, or entirely new test chambers created at will.
 * Character Development: Of all people,  gets this throughout the second half of the game. It gets hilariously subverted
 * Chekhov's Gun
 * Very near the start of the game, it is said that all Aperture Science personality constructs keep working with as little as 1.1 volts, the same amount a potato battery provides,
 * It is revealed in one of the intermediate levels that the white conversion gel gains its properties from . Later, during the final battle,  gains the upper hand, preventing Chell from replacing his AI core with GLaDOS'. When an explosion rips the roof off the facility, Chell.
 * Chekhov's Skill: At the end of the co-op campaign, ATLAS and P-body need to . How do they accomplish this? By.
 * Cliffhanger Copout: The ending of the first game does not quite match up with the second, even with the Lab Rat comic. The first game ends with GLaDOS exploding due to the incineration of the cores, Chell and GLaDOS landing on the surface, Chell getting dragged back inside, the cake not being a lie, the other cores waking up, and GLaDOS filing a report about not really being dead. The sequel reveals that the cores are separate entities and not vital components (so why the explosion?), GLaDOS' body changing shape and getting back inside the facility offscreen (Party Escort Bots like the one that dragged Chell?), the cake being ignored (though that part was a joke), the cores being cut (see What Happened to the Mouse? below), and GLaDOS actually being dead (well, besides reliving her death over and over) until revived.
 * Cloudcuckoolander: Cave Johnson's story is elaborated quite a bit in this game from the original supporting material. On the one hand, a lot of what we thought we "knew" about Aperture and Johnson turns out to be fabrication, but from what we hear of Johnson from the man himself, he still...had a screw or two loose. Much of which came from what seemed to be pure stubbornness in keeping Aperture alive. As the cost of testing and keeping the facility up and running grew, as he dumped more money into making the facility bigger and self-sufficient to recoup costs, you can hear his sanity slipping in his messages.
 * The entire Aperture Science facility is basically Cloudcuckooland, considering that the only sane individual there is arguably Chell who only gets that consideration because she's the player character—this trope is even more present than in the original Portal, due to the fact that Portal 2 now has more than two characters.
 * Combat Stilettos: Played with. Chell wears "Long-Fall Boots" which are visually similar to high-heels. She is required to wear them to cushion very fast, very high falls in order to prevent her legs from being crushed.
 * Comedic Sociopathy: Cave Johnson deserves an award for this, if nothing else. The promo videos for Aperture Science's technologies make a Running Gag out of the broken fragments of the test subjects being swept into incinerators while their inventions are treated with utmost care. The co-op mode encourages it in players, thanks to What Measure Is a Non-Human? combined with Video Game Cruelty Potential.
 * Computer Voice: GLaDOS, Wheatley, the Turrets and the Cores obviously, but as you navigate the first ruined test chambers a new, male, voice guides you and later announces general information about what's going on in the facility. It responds to what GLaDOS and Wheatley say in very limited fashion so was most likely the voice of the Aperture Science computer systems before GLaDOS came along, and is a back-up system for when she's unavailable.
 * Continue Your Mission, Dammit!: GLaDOS and Wheatley (especially Wheatley) have a lot of things to say if you linger in any one area for too long. You'll miss a good 75% of the dialogue in the game unless you take your time. In fact, it's literally impossible to hear all the dialog in a straight playthrough.
 * Continuity Drift: A lot of the Enrichment Center's aesthetic design was given an upgrade between games, even though all of the systems that could've replaced it all were deactivated.
 * Continuous Decompression: Justified.
 * Convection, Schmonvection: If you trust the signs on the walls, the Aperture facility testing shafts extend some 5 km (3 miles) below ground. At that depth the ambient temperature would be something like 70 °C (160 °F) -- way more than enough to cause third degree burns. However, maps of the place suggest that even as far down as that, Cave Johnson had built massive structures. Justified by the lowest levels being made of asbestos, a fantastic insulator.
 * Cool and Unusual Punishment: GLaDOS mentions a room entitled "The chamber where all the robots scream at you", also briefly alluded to by Wheatley in an earlier part of the game.
 * Cool Gate:
 * Portals.
 * The epically massive doors that seal off the old Aperture Science facility. The commentary ventures the notion that they're the biggest doors ever depicted in a video game. It also notes that they deliberately placed a as a joke.
 * Cores and Turrets Boss: Inverted with respect to the first game;
 * Corrupt Corporate Executive: Cave Johnson.
 * Coup De Grace Cutscene: It takes more than just a portal gun to finish off the Final Boss.
 * Creepy Child: In one of Perpetual Testing clips, Cave views Greg's daughter as one of these.
 * Creepy Monotone: GLaDOS seems to have found an interesting midpoint between her two voices in the first game. She sounds more like her early, robotic voice with just a hint of the deeper, sexier voice she used in the Final Battle. This makes almost everything she says have just a tinge of bitterness, which is probably the point. Later in the game, she abandons her monotone and begins speaking with a more human cadence. Until
 * Crazy Prepared: The Enrichment Centre is designed to continue testing its subjects in the face of The End of the World as We Know It, even with most of the facility in ruins. Recordings detailing how to cope with all manner of different Apocalypse How scenarios are provided for the player. The machinery is even designed to run on minimal voltage so it can continue to function if power is scarce.
 * Creative Closing Credits/Credits Gag: Like the first game, the ending song plays over a text screen that displays the lyrics in the form of a computerized personnel file report.
 * Curse Cut Short: The curse in question is relatively mild, but probably necessary to maintain the E10+ rating.

"Four-part plan is this: One, no portal surfaces. Two, start the neurotoxin immediately. Three, bomb-proof shields for me, leading directly into number four: bombs. For throwing at you."
 * Cute Machines: There's Wheatley and the other cores, the turrets, the co-op mode robots, and.
 * Cut Lex Luthor a Check: If Cave Johnson weren't completely insane (and the world hadn't freaking ended within a few years), the inventions of his company would have made him the richest man on Earth. Completely negating the possibility of injury from falling, functional and compact teleportation technology (something Black Mesa, to the time of Half-Life 2, never managed reliably), real AI (albeit murderous in some incarnations)? Amazing. To a lesser extent, the "Heimlich Counter-Maneuver", while a commercial failure, seems to have been quite popular with the government, who somehow managed to use it to let high ranking Fatah members choke to death on lamb chunks. The commentary track confirms that Aperture Science's Fatal Flaw isn't their science, but that they are horrible at marketing. And, well, basic product safety.
 * Cutscene Power to the Max: In the trailer faux-advert demonstrating the shock absorbing boots, Chell engages in acrobatic awesomeness, leaping, diving and somersaulting through portals. In game, her jump animation is less than 10 frames.
 * At the end where, you would die on the spot in any other context, but instead
 * Cutting the Knot: How Wheatley hacks open the door in the turret testing room..
 * Dangerously Genre Savvy: At the start of the Final Battle,


 * Darker and Edgier: In comparison to Portal, triumphantly so. Which is funny, considering that due to the absence of blood in Portal 2, it actually has a lower rating.
 * Dark Reprise:
 * Chell's initial check-up at the beginning of the game is heralded by the cheery Aperture Science fanfare. The next time she's woken up, the fanfare is corrupted/garbled and the surrounding music is in a minor key.
 * The triumphant music that begins to play when Wheatley is enjoying himself
 * Also, the music that plays at  is also recycled as the chord progression of the final boss theme.
 * There is also a four-note "danger" theme that, not surprisingly, tends to show up when Wheatley is doing something particularly stupid and/or risky. However, this theme generally isn't focused on too much - it's merely an interjection that plays occasionally during some of the other themes. The one time it manages to become a central theme of the music, with the force of an orchestra playing it?
 * Deadly Neurotoxin: Puts in a few repeat appearances.
 * Death by Irony:  is defeated by  Also ironic to the player in that   Even more so when you consider that
 * Death Glare:
 * GLaDOS gets in a good one for having almost no face.

"GLaDOS:"
 * Death Is Cheap: The two robots in co-op mode are uploaded into a new body whenever they die, as illustrated by the trailer. One of the robots dismisses its destruction (and the other robots' role in it) with a wave of its hand. The Portal 2 team say this is a major reason for using robots as the co-op mode characters. They wanted your (many) deaths at the hands of badly-planned maneuvers, incompetent or jerky co-players and just larking about to be funny and more consequence-free than showing humans being crushed, shot or falling in acid and so forth.
 * Death Trap: GLaDOS and use them with reckless abandon this time around, partly out of frustration for how hard it is to kill Chell.
 * Department of Redundancy Department: This is all over Aperture Science. The prerecorded announcements, Cave Johnson, and GLaDOS herself all tend to repeat phrases.
 * Department of Redundancy Department: This is all over Aperture Science. The prerecorded announcements, Cave Johnson, and GLaDOS herself all tend to repeat phrases.

{{quote| {{spoiler|1=GLaDOS: Well}}, This Is the Part Where {{spoiler|he kills us!}} {{spoiler| Wheatley: Hello!}} This is the part where {{spoiler|I kill you!}} Chapter 9: The Part Where {{spoiler|He Kills You.}} Achievement Unlocked: The Part Where {{spoiler|He Kills You}} The achievement's subtitle: "This is that part". Soundtrack: The Part Where {{spoiler|He Kills You}}. {{quote| Proctor's note: Test subject is abnormally stubborn. She never gives up. Ever. Rejected. Do not test! }} {{quote| Valve: {{spoiler|Combined might of Internets (sic) is terrifying.}}}} {{quote| "Grab me! Grab me! Grab me! Grab meeeeeeeeeeeeeeeeeeeeeee..."}} {{quote| GLaDOS: I'm not going to lie to you, the odds are a million to one, and that's with some generous rounding. Fact Sphere: The probability of you dying violently within the next 5 minutes is 87.61 percent. }} {{quote| GLaDOS: {{smallcaps| Yeah! Yeah! TAKE the lemons!}}}} {{quote| GLaDOS: {{smallcaps| Remember when I talked about smelly garbage being useless? That was a metaphor. I was talking about you.}}
 * And later, used for a Crowning Moment of Funny:
 * Determinator: According to Chell's personnel file, she's on the far side of the bell curve for tenacity.
 * Lampshaded lightly (and possibly unintentionally by {{spoiler|Chell's potato experiment; whereas all the other experiments show dead, shriveled potatoes, hers has become massively overgrown and is probably responsible for part or all of the vegetation that's taken over the complex... making it one very determined potato!}}
 * Cave Johnson had a particular always-move-forward attitude that informed the way he ran Aperture, in conjunction with the fact that he had all the sanity of a waffle. He was convinced that, sooner or later, everything Aperture produced could be brought back around to somehow improving shower curtain technology, which is what Aperture theoretically produced. If they couldn't, they'd still find some way to grossly misapply it.
 * The Dev Team Thinks of Everything:
 * There are quite a few lines of dialog that you won't hear unless you wait a very long time in some areas, or commit blatant Violations of Common Sense.
 * If you manage to get yourself trapped in a test chamber, whoever is acting as Mission Control will comment on it and rescue you. With biting sarcasm, in GLaDOS' case.
 * There's also an in-universe example—Aperture Science apparently saw fit to make a recording that would allow them to continue running tests after The End of the World as We Know It.
 * There is a secret Ratman den that shuts itself up after a certain amount of time. If you go in there during commentary mode, you'll see a commentary node. You'd think it's about the Ratman's Dens. It's not. It's nonsensical, ear-screeching noise that will make you wish you had your ear-canals emancipated. {{spoiler|It's the sound translation of an image file, which details the pre-announcement Portal 2 ARG. You know, the one that also used image-to-sound converters.}}
 * {{spoiler|They estimated that the whole project would only take 7 hours for the combined effort of worldwide fans to decode. They were only off by a few minutes.}}
 * Did Not Do the Bloody Research: For an E10+ game, Wheatley likes to use the word "bloody" quite a bit. He's quite the cheeky little personality sphere.
 * Disc One Final Boss:.
 * Disney Villain Death: ending.
 * Disposable Vagrant: After the "1968 Senate hearings on missing astronauts", Aperture was nearly broke and was forced to hire street bums to stumble through the test courses for $60 each—with a potential $60 bonus if they allowed Aperture to perform horrific medical experiments on them along the way. The architecture of the test chambers reflects this shift, as there are signs informing test subjects to keep moving, not leave belongings behind, and not touch the glass. For bonus points, they only get their money if they fill out the forms and sign legibly. As with the earlier tests, there are strong implications that few, if any, survived.
 * Distracted by the Sexy: {{spoiler|Wheatley tries to pull this off when attempting to convince Chell to jump down into a bottomless pit, claiming that there's a sexy boy band down there that hasn't seen a woman in years. Whether it works or not is up to the player, but you get an achievement for falling for it.}}
 * Disturbing Statistic:
 * The Ditz: {{spoiler|Deconstructed with Wheatley. In the beginning his incompetence is endearing and harmless, but after The Reveal you find out that his incompetence is justified and extremely dangerous.}}
 * Wheatley seems fully aware that he's the ditz. And he does not like it.
 * Does This Remind You of Anything?:
 * The comments Wheatley makes while watching {{spoiler|1=you and GLaDOS get through the tests}} makes it sound like he's enjoying it a bit too much. {{spoiler|1=GLaDOS}} confirms it, stating that the system gives the AI a euphoric response for concluding every test, that gets smaller as you gets used to it, and  {{spoiler|Wheatley doesn't have the intellectual capacity to overcome its withdrawal symptoms.}} To drive the point home, that chapter ("The Itch") is titled "Addiction" in the French version.
 * GLaDOS sounds awfully excited at the end of the co-op campaign.
 * When you hear Cave Johnson's lemon speech, GLaDOS sounds... very enthusiastic about it.
 * According to an Urban Legend of Zelda (which was confirmed false) the sound clips of {{spoiler|1=Caroline being forced into GLaDOS's brain}} sounded so wrong, that JK Simmons refused to read his lines, and the scene/recording/whatever it might have been was Dummied Out.
 * The Dog Was the Mastermind: The villain of the Peer Review DLC course? {{spoiler|1=The bird who frightens Wheatley and GLaDOS so much.}}
 * Do Not Go Gentle: Cave's "lemons" rant.
 * Don't Explain the Joke: A Running Gag with GLaDOS and.

{{spoiler|Wheatley:}} You two are going to LOVE this big surprise. In fact, you might say you're going to love it... to death. Love it... until it kills you. 'Til you're both dead. (Beat) Hehehe. Alright? I don't know if you're, uh, picking up on what I'm saying here, but... {{spoiler|1=GLaDOS: (sighing) {{smallcaps| Yes, thanks. We get it.}}}} }} {{quote| "Look at that sad little octopus! Ha!"}} {{quote| ''Muhahahaha! HAHAHAHAHAhaha… haaa, this is tiring.''}} {{quote| "Let the games begin."}} {{quote| GLaDOS: {{smallcaps|Don't disappoint me -- or I'll make you wish you could die.}}}} {{quote| GLaDOS: {{smallcaps|It didn't matter to me, I was just in it for the science.}}}} {{quote| GLaDOS: {{smallcaps|We've both said a lot of things that you are going to regret, but I think we can put our differences behind us. For Science!. You Monster!.}}}} {{quote| GLaDOS: {{smallcaps| We're going to have fun -- with Science!}}}} {{quote| Cave Johnson: Good enough for science. Not Aperture Science!}} {{quote| Rick: I'll tell ya, it's times like this I wish I had a waist so I could wear all my black belts. Yeah, you know, I'm a black belt in pretty much anything: karate, larate, jiu jitsu, kick punching, belt making, taekwondo... bedroom.}} {{quote| {{spoiler|Space Core: Gotta go to space. Yeah. Gotta go to space!}} {{spoiler|Wheatley: Nobody's going to space, mate!}} }} {{quote| {{spoiler|Wheatley: Take one last look at your precious human moon, 'cause it cannot help you now!}}}} {{quote| Cave Johnson: Those of you helping us test the repulsion gel today, follow the blue line on the floor. Those of you who volunteered to be injected with praying mantis DNA, I've got some good news and some bad news. The bad news is we're postponing those tests indefinitely. The good news is we've got a much better test for you: fighting an army of mantis men! Pick up a rifle and follow the yellow line. You'll know when the test starts. GLaDOS: {{smallcaps|Okay, so the bad news is that the tests are my tests now. So they can kill us. The good news is... well, none so far, to be honest. I'll get back to you on that.}} }} {{quote| Wheatley: Never played cards, been meaning to learn. [...] Ace of fours! The best hand, I imagine.}} {{quote| Wheatley: Are you alright? Yes or no? Game Hint: [Jump] Talk Wheatley: Ok, what you did there was jumping...say Apple, aaa-pple. Game Hint: [Jump] Say Apple }} {{quote| GLaDOS: {{smallcaps|And then you showed up. You dangerous, mute lunatic.}}}} {{quote| "Ever wondered what a parallel universe you might be like? Well, stop wondering, because you’re just Hitler. Every parallel universe ever. You. Hitler. We can’t figure it out. Anyway, if you meet him in the next test, don’t kill him. I know, I know. But trust me, it’d be bad."}} {{quote| : {{spoiler|Actually, why do we have to leave right now?}}}} {{quote| GLaDOS: {{smallcaps| These next tests require cooperation. Consequently, they have never been solved by a human.}}}} {{quote| Cave Johnson: Fact: the key to any successful cooperative test is trust. And as our data clearly shows, humans cannot be trusted. The solution? ROBOTS! Then... fire the guys who made those robots and build BETTER robots!}} {{quote| Cave Johnson: BAM! Robots gave us six extra seconds of cooperation. Good job, robots!}} {{quote| GLaDOS: {{spoiler|{{smallcaps|For the record, you }}{{smallcaps|are}}{{smallcaps| adopted. And That's Terrible. But just work with me.}}}}}} {{quote| GLaDOS {{smallcaps|Since it doesn't look like we're going anywhere... well, we are going somewhere. Alarmingly fast, actually. But since we're not busy other than that, here's a couple of facts.}}}} {{quote| Cave Johnson: We're just throwing science at the wall and seeing what sticks.}} {{quote| Oracle Turret: I'm different... Defective Turret: *fires ineffectually at target* click-click-click "Aww, I'm one of the bad ones, aren't I?" }} {{quote| GLaDOS: {{spoiler|{{smallcaps|I think that one was about to say 'I love you'.}}}}}} {{quote| Wheatley: {{spoiler|Holmes versus Moriarity. Aristotle versus MASHY-SPIKE-PLATE!}}}} {{quote| GLaDOS: {{smallcaps| Federal regulations require me to remind you that this next test chamber... is looking pretty good. That's right, the facility is completely operational again.}}}} {{quote| "Alright, this next test may involve trace amounts of Time Travel. So, word of advice: If you meet yourself on the testing track, don't make eye contact. Lab boys tell me that'll wipe out time. Entirely. Forward and backward. So do both of yourselves a favor and just let that handsome devil go about his business."}} {{quote| Cave Johnson: All right, let's﻿ get started. First test involves something the lab boys call "Repulsion Gel". You're not part of the control group, by the way. You get the gel. Last poor son of a gun got blue paint! Ha ha ha! ... all joking aside, that did happen. Broke every bone in his legs. Tragic, but informative! Or so I'm told." "The lab boys just informed me that I should not have mentioned the control group. [...] I pay the bills here, I can talk about the control group all damn day!" }} {{quote| GLaDOS: {{smallcaps| Warning devices are required on all mobile equipment. However, alarms and flashing hazard lights have been found to agitate the High Energy Pellet, and have therefore been disabled for your safety.}}}} {{quote| Science isn't about "Why?", it's about "Why not?!". You ask: "Why is so much of our science dangerous?" I say why not marry safe science if you love it so much? In fact, why not invent a special safety door that won't hit you in the butt on the way out because you are fired!}} {{quote| "They are sentient, you know. We just have a lot of them."}} {{quote| GLaDOS: {{smallcaps|We're a lot alike, you and I. You tested me, I tested you. You killed me, I -- oh, no, wait. I guess I haven't killed you yet. Well. Food for thought.}}}} {{quote| Fact Sphere: Dreams are the subconscious mind's way of reminding people to go to school naked and have their teeth fall out.}} {{quote| Wheatley: You did WHAT?!}} {{quote| GLaDOS: Well, what does a neck-bearded old engineer know about fashion? He probably— Oh, wait. It's a she. Still, what does she know? Oh wait, it says she has a medical degree. In fashion. From France.}} {{quote| Wheatley: I'll just hack it, not a problem. Ok, AAAAAA. That's -- I thought that was gonna be it; I'm surprised. AAAAA...C. Wrong again? That's surprising...that's...wait, I didn't do B, did I? We should be making a note of these. Have you got a pen?" }} {{quote| {{spoiler|The best solution to a problem is usually the easiest one. And I'll be honest. Killing you? Is hard.}}}} {{quote| Cave Johnson: All right, I've been thinking. When Life Gives You Lemons, don't make lemonade. GLaDOS: {{smallcaps|Yeah.}} Cave Johnson: Make life take back the lemons back! GLaDOS: {{smallcaps|Yeah!}} Cave Johnson: Get mad! GLaDOS: {{smallcaps|Yeah!}} Cave Johnson: 'I don't want your damn lemons! What am I supposed to do with these?!' GLaDOS: {{smallcaps|Yeah, take the lemons...}} Cave Johnson: Demand to see life's manager! GLaDOS: {{smallcaps|Yeah!}} Cave Johnson: Make life rue the day it thought it could give Cave Johnson lemons! Do you know who I am? I'm the man who's gonna burn your house down! WITH THE LEMONS! GLaDOS: {{smallcaps|Oh, I like this guy.}} Cave Johnson: I'm gonna get my engineers to invent a combustible lemon that BURNS YOUR HOUSE DOWN! GLaDOS: {{smallcaps|BURN HIS HOUSE DOWN! Burning people! He says what we're all thinking!}} }} {{quote| {{spoiler|1=GLaDOS: {{smallcaps| Look, even if you think we're still enemies, we're enemies with a common interest: revenge. You like revenge, right? EVERYBODY likes revenge! So LET'S! GO! GET SOME!}}}}}} {{quote| Announcer: Sarcasm self-test complete. GLaDOS: {{smallcaps|Oh, good. That's back online.}} }} {{quote| Announcer: Corrupted core, are you ready to start? Wheatley: What do you think? Announcer: Interpreting vague answer as "YES." Wheatley: No no no no no! Didn't pick up on my sarcasm... }} {{quote| "The Schrödinger's Cat paradox outlines a situation in which a cat in a box must be considered, for all intents and purposes, simultaneously alive and dead. Schrodinger created this paradox as a justification for killing cats." }} {{quote| GLaDOS: {{smallcaps|Look at you, soaring majestically through the air. Like an eagle. Piloting a blimp.}}}} {{quote| Fact Sphere: William Shakespeare did not exist. His plays were masterminded in 1589 by Francis Bacon, who used a Ouija board to enslave play-writing ghosts.}} {{quote| GLaDOS: Did you know that people with guilty consciences are more easily startled by loud nois-[train horn]}} {{quote| Wheatley: I mean, listen: we should get our stories straight, alright? If anyone asks -- and no-one's going to ask, don't worry -- but if anyone asks, tell them as far as you know, the last time you checked everyone looked pretty much alive.}} {{quote| GLaDOS: {{smallcaps|So. This cat loves lasagna so much that he eats all of the lasagna in his house. Oh, apparently it's not the cat's house, or his lasagna. Oh good! The man who owns the lasagna is furious! The end. The end?! That's not funny. Do either of you feel like laughing? All right, I'm pulling you out.}}}} {{quote| Rick: "I am a coiled spring right now. Tension and power. Just... I'm a muscle. Like a big arm muscle, punching through a brick wall, and it's hitting the wall so hard the arm is catching on fire. Oh yeah."}} {{quote| Wheatley: ''I. AM NOT. A MORON!'' (and then with Punctuated Pounding: {{spoiler|Could a MORON! PUNCH! YOU! INTO! THIS! PIT!}}) GLaDOS: {{smallcaps|This. Sentence. Is. FALSE}} (to self) {{smallcaps|Don't think about it don't think about it...}} GLaDOS: {{spoiler|{{smallcaps| LET'S! GO! GET SOME!}}}} Rick: THIS ROBOT OWES! YOU! MONEY! }} {{quote| Announcer: All Military Androids have been taught to read and given a copy of the Three Laws of Robotics. To share.}} {{quote| Announncer: Nuclear core overheating! GLaDOS: I think we're in trouble. }} {{quote|  {{spoiler|Wheatley}}: What, are you still alive? You are joking! You Have Got to Be Kidding Me!! {{spoiler|Well, I'm still in control. And I have no idea how to fix this place! Oh, you had to play bloody cat and mouse, didn't you? While people were trying to work. Yes, well, now we're all going to pay the price, because we are all going to bloody die! Oh, brilliant, yeah. Take one more look at your precious human moon. Because it cannot help you now!}}}} {{quote| {{spoiler|After fizzling the Companion Cube you take out of the test chamber:}} GLaDOS: {{smallcaps|They}} {{smallcaps|are}} {{smallcaps|sentient, of course. We just have lots of them.}} }} {{quote| GLaDOS: I hope that was some kind of joke. GLaDOS: How can you fail this? It's not even a test! GLaDOS: I didn't think we'd have to keep track of the number of times you've died in the hub. }} {{quote| GLaDOS: You really do have brain damage, don't you?! I can't believe you came back. [player jumps into hole] {{spoiler|Wheatley: Oh! Wow! Good! I did not think that was going to work.}} Achievement Unlocked }} {{quote|  {{spoiler|Wheatley}} Now who's a moron? Could a moron punch! you! into this! pit!? '''HUH?!? COULD A MORON DO THAT!?'''}} {{quote| "Why don't they marry safe science if they love it so much?"}} {{quote| "Maybe you should marry that thing since you love it so much. Do you want to marry it? WELL I WON'T LET YOU. How does THAT feel?"}} {{quote| GLaDOS: {{smallcaps|Killing you... is hard.}}}} {{quote| GLaDOS: {{smallcaps|{{spoiler|I know we're in a lot of trouble and probably about to die.}} But that was worth it.}}}} {{quote| "{{smallcaps|Congratulations. Not on the test; most test subjects come out of hibernation terribly undernourished. I want to congratulate you on beating the odds and somehow managing to pack on a few pounds.}}"}} {{quote| "{{smallcaps|One of these times you'll be so fat that you'll jump, and you'll just drop like a stone. Into acid, probably. Like a potato into a deep fat fryer.}}"}} {{quote| "...Just ten pounds of useless dead weight. Soon to be two hundred and ten. Fatty."}} {{quote| GLaDOS: {{smallcaps|Core transfer? Oh, you are kidding me.}} {{spoiler|Wheatley}}: What, are you still alive?! You are joking. You have got to be kidding me! }} {{quote| GLaDOS: {{smallcaps|What are you doing? YOU MONSTER! They're one of us.}}}}
 * Door Step Baby: GLaDOS claims Chell was this.
 * Downloadable Content:
 * On the purely cosmetic side, the Robot Enrichment Center allows players to download an array of hats, skins, and so forth, which can be applied to the co-op robots. Of particular note are the larger selection of gestures, such as the thumbs-up P-body does at the end of the game.
 * A free DLC with playable content was released on October 4, 2011 containing a new co-op campaign, and leaderboards/challenges for least time and portals, like in the first game. Another DLC was made available to those with the Razer Hydra controller (released in June), adding chambers where the portal gun has properties similar to the Physgun in Garry's Mod.
 * Another DLC titled "The Perpetual Testing Initiative" adds a creative gameplay mode where players can design their own test chambers and share them over Steam.
 * Dramatic Pause: Happens when you {{spoiler|fire your last portal.}} In fact, it lasts for just under 3 seconds, {{spoiler|the time it takes for light to reach the moon and bounce back.}} Developer commentary says the pause  {{spoiler|and the Twinkle in The Sky afterward}} was implemented at this scene just to preserve this fact while letting the player know that what they did worked.
 * Drill Sergeant Nasty: GLaDOS attempts to become one during the Peer Review DLC - surprisingly, she's not very good at it.
 * Drunk with Power: {{spoiler|1=Wheatley, once he takes over GLaDOS's body and thus the entire Enrichment Centre.}}
 * Dummied Out: A fourth Mobility Gel, Adhesion Gel. There's still enough code left over for a skilled programmer to fake it; had it made it into the game, it would have allowed the player to walk on walls or ceilings. It was removed because testers got disoriented and couldn't complete test chambers where they needed to use it.
 * Durable Deathtrap: Subverted or played straight depending on what part of the game you're in. The Enrichment Center as we know it is dilapidated and becoming overgrown by plants, and in some places bits of the testing rooms are malfunctioning. When you go deep underground to the earliest iteration of the Enrichment Center, all the catwalks leading to the test chambers are busted, but the test chambers themselves are in perfect working order, as are the Material Emancipation Grids, the pumps dispensing Mobility Gels, and the recordings from Cave Johnson. Granted, unlike most examples of the trope, these facilities have only had a few decades to a century or so to decay, instead of the usual thousands of years, but it's still damn impressive.
 * DVD Commentary: Repeated in this game, along much the same lines as the first.
 * Earn Your Happy Ending: Though at first it may appear to be a Shaggy Dog Story, if you examine it closely Portal 2 ends on a hopeful note. {{spoiler|1=GLaDOS is back in control, and claims to have deleted Caroline and her conscience, but lets Chell leave peacefully, and the ending song hints that Caroline isn't quite gone.}} And without the events of the game, {{spoiler|1=GLaDOS would still be the monster she was at the beginning, experiencing her death over and over, while Chell would be asleep indefinitely.}} Without Wheatley, nothing would have changed that.
 * Elaborate Underground Base: After a bit of Foreshadowing from Wheatley, we get to see just how astoundingly elaborate the Aperture Science facility really is.
 * The End: Spoken, rather than shown as a title card. {{spoiler|During The Stinger, Wheatley is in space, apologizes to the player,}} and finishes by saying, "The end." The way this is pulled off, it's a real Player Punch.
 * Enemy Mine: Chell is forced to work with {{spoiler|1=GLaDOS after Wheatley's Face Heel Turn}}.
 * Escape From the Crazy Place: Repeated from the first game, with bonus crazy for the discerning client.
 * Everything's Squishier with Cephalopods: The trailer for The Perpetual Testing Initiative explains that Cave Johnson had at one point outsourced test chamber construction to a race of sapient octopuses from another dimension. The octopuses are essentially treated by Cave as slave labor, which he finds rather funny.
 * Evil Laugh: Your first clue that {{spoiler|putting Wheatley in charge may not have been such a hot idea. Or rather, the final confirmation after two minutes of nagging suspicion, as he's been talking about how small you are and how big he is.}}
 * He does a more humorous one when there are "3 tests left"
 * When you sabotage the turret line, the defective turret used as the new template lets one out whenever a proper turret is rejected.
 * Evil Sounds Deep: {{spoiler|Wheatley gets this occasionally after his Face Heel Turn, most notably:}}
 * Invoked later when you reach {{spoiler|Wheatley's}} lair. The first word, "Welcome," is spoken normally, followed by "TO MY LAIR" being spoken in a far deeper tone with an echo for dramatic effect.
 * Evil Is Hammy:
 * Exactly What It Says on the Tin: "This is the part where {{spoiler|he kills you}}" with bonus Department of Redundancy Department thrown in.
 * Exact Time to Failure: Each phase of the Final Boss battle has a distinct timer, to the point that when the timer for the reactor explosion is disabled, the Enrichment Center activates a self destruct sequence to remove the uncertainty of not having a countdown until everything blows up.
 * Expospeak Gag: Wheatley is full of these. During the opening sequence, he attempts "a manual override on this wall", after mistaking it for a docking station. In other words, he repeatedly rams a room into the wall until it breaks. Later, he asks Chell to turn her back while he "hacks" a door open. He smashes the glass in the window. (This can be seen if you fire a portal on the wall ahead of you.)
 * Aperture Science is a fan of these in both games; Portal 2 is notable for terms such as Thermal Discouragement Beam, Excursion Funnel and Aerial Faith Plate to name a few.
 * In the co-op campaign, Atlas and P-Body encounter the "Edgeless Safety Cube".
 * Face Heel Turn: {{spoiler|1=Wheatley, after he takes over GLaDOS's body.}}
 * Fan Service: Many people, especially those who hadn't played the first Portal, figured this was why Chell neglects the upper portion of her jumpsuit. In fact it's pretty hard to get a good look at her at any point during the game even if you're trying to. Developer commentary said the idea was that she's "rolled up her sleeves" and means business this time.
 * Fan Service Pack
 * Fast-Forward Gag: At one point, GLaDOS says that she has to tell you something important about the testing chamber you're in. Being GLaDOS, she skips through the warning quite quickly. Slowed down, she's reciting a passage from Moby Dick.
 * Fate Worse Than Death:
 * GLaDOS to the cooperative mode robots in their trailer:
 * GLaDOS notes that she has a "black box" function in her programming that saves the last two minutes of her life. The entire time she was "dead", she had to constantly relive Chell killing her again and again. She then in turn threatens this upon Chell with this, suggesting she may even learn how to reanimate the dead so she can resurrect Chell again and again.
 * GLaDOS also mentions she feels death is too good for . See Rasputinian Death.
 * Feathered Fiend: Well, at least from GLaDOS's point of view, for at least part of the story.
 * Feigning Intelligence: Basically all Wheatley does. After getting tired of being called a moron, he spends one test chamber playing classical music and claiming to read Machiavelli.
 * Filk Song: Two, both of them dedicated to our favorite personality construct! Behold, "Wheatley's Song" by Miracle of Sound, and "Why, Wheatley, Why?" by BrainForce V.
 * Force Field Door: Space warden!Cave discovers the problem with these the hard way.
 * Foreshadowing:
 * Wheatley comments that Aperture Laboratories is even bigger than the Enrichment Center would suggest, and that the lower levels go down for miles. Guess where you eventually end up exploring?
 * If you save the turret from redemption, it will start babbling a sequence of seemingly random lines that don't seem connected in any way. Everything it says is actually plot-relevant, including {{spoiler|1=quotes from Cave's lemon speech ("Get mad!", "Don't make lemonade!"), referencing the lower levels of Aperture ("The answer lies beneath us."), spoiling The Reveal ("Her name is Caroline. Remember that.") and mentioning Prometheus, who gave Man knowledge and was punished by being cast into the underworld and pecked at by birds - which is exactly what happens to GLaDOS (tells you what Wheatley was built for, is knocked down into Old Aperture for it and, yes, pecked by birds.)}}
 * Near the beginning of the game there's a rather unmemorable line about "All personality constructs remain fully functional at 1.1 volts." A couple chapters later there are a few wrecked science fair displays featuring potato batteries. {{spoiler|1=A few rooms after the potato batteries, GLaDOS (a personality construct) is shoved into a potato.}} Which produces approximately 1.1 volts of electricity.
 * The game deserves special mention for {{spoiler|the ending. "Lunacy" doesn't even begin to describe it.}} It crops up everywhere throughout the game, which makes the ridiculousness of it amazingly plausible in context. Here's a list:
 * The painting you see at the beginning of the game shows a nice countryside during the day. {{spoiler|After the Time Skip, the scene has changed to a night one and the painting has a prominent full moon in the sky.}}
 * Several of the Ratman's dens have a poem about eyes, with some of the eyes drawn as {{spoiler|phases of the moon. In the area where you pick up the first portal gun, hanging from the roof is a mural depicting the moon's phases.}}
 * One of Cave Johnson's pre-recorded messages mentions that {{spoiler|the Conversion Gel used to create instant portal surfaces was developed from moon rocks, which are an excellent portal conductor.}}
 * During the end boss, {{spoiler|the Space personality core is the first one you attach to Wheatley in order to get his body to reject him. It constantly rants things like, "space, space, gotta go to space!"}}
 * In the Lab Rat comic, {{spoiler|1=the other scientist who was talking with Rattmann about GLaDOS compares artificial intelligence to other scientific frontiers like - among other things - moon launches in the Sixties. Rattmann cynically states that he'd rather go to the moon than deal with AI.}} Of course, this may just be a coicidence, considering how much the story was progressed at that point.
 * {{spoiler|"I'm telling you, this is our generation's moon shot."}} This may also be a coincidence.
 * {{spoiler|When the VA of Wheatley's placeholder voice, Richard Lord, was reassuring the public about Stephen Merchant replacing him, he mentioned that he was "over the moon" with the decision.}} Again, this may just be a coincidence, as this statement was made early in development.
 * One of the Fact Core's "facts" is that "{{spoiler|The moon orbits the Earth every 27.32 days.}}"
 * When Rick plans a one-liner for when Chell finishes off, he tells her to {{spoiler|"stand back, 'cuz I'm about to zing him into space.}}
 * {{spoiler|"NOBODY'S GOING TO SPACE, MATE!"}}
 * Though the one that really takes the cake is a Dummied Out line by Cave Johnson in which he {{spoiler|explicitly threatens to use a weaponized portal to the moon against someone, saying: "You hear me? I invented portals! I can put a doorway on the moon and another into your parking lot! Let’s see how many patents you steal when you’re floating around in outer space, you—"}} This was probably Dummied Out because it was a bit too obvious.
 * The song that is added to the BGM when you hold the Companion Cube in an early test chamber {{spoiler|is the turret opera song.}}
 * The method you use to take down the first boss is repeated almost precisely for the last boss. With a bit of a twist, of course.
 * For Science!:
 * Despite all the humorous highlighting—which sometimes bordered on the levels of lampshading—it's played perfectly straight in this line explaining why GLaDOS didn't care about {{spoiler|building up a tolerance to the euphoric response to testing}}:
 * GLaDOS invokes this trope in a line included in the trailer.
 * In a 30 second television ad showing off P-Body and Atlas:
 * Cave Johnson seems to think Aperture Science is a step above ordinary science.
 * Freeze-Frame Bonus: A threefer in the Perpetual Testing Initiative trailer. The easiest is the person from the Valentine's Day trailer, who still has the diamond on their lap. The other two are more quick- one person's watching porn on their computer (at work, even), and the other's watching the still-unreleased Meet The Pyro.
 * Frickin' Laser Beams: The "Thermal Discouragement Beams" in Portal 2 act like normal lasers, save for being fully visible. They also live up to their name, as they don't instantly kill you but rather hurt enough to keep you from simply walking through them. Amusingly, the graphic displayed when they are introduced implies that they were developed as a tool to keep office workers at their desks. Alternatively, Aperture was just idiotic enough to fire the laser through offices, just because of where they decided to build the main device.
 * From Nobody to Nightmare: {{spoiler|1=Wheatley, who goes mad upon being plugged into GLaDOS' mainframe. Caroline is also an example, given that she became part of GLaDOS after her Brain Uploading.}}
 * G-Rated Drug: GLaDOS states explicitly that there is a mechanism in the facility-controlling machine that releases a euphoric sensation when testing. While GLaDOS claims to have built up a tolerance, no longer affected by it, {{spoiler|when Wheatley gains control of the facility, he shows a sort of addiction to testing, which is fine... until he builds up a tolerance and goes looking for a better high}}.
 * Gainax Ending: Zig Zagged. The game ends with GLaDOS {{spoiler|kicking Chell out via elevator ride. This trope comes into play when the elevator stops at several turrets, which instead of firing upon her, start singing. This continues up several more floors, culminating in an entire choir of singing turrets. The choir is then forgotten as the elevator makes it to the surface, revealing blue skies and a field of wheat. And a singed companion cube being spat out from the elevator as well.}}
 * Even more so in co-op. {{spoiler|You open a giant vault discovering thousands of humans in stasis and as soon as the robots do their Victory Dance they are blown up and the credits roll. The blowing up makes sense, but seriously, what?}}
 * Game Breaking Bug: {{spoiler|In the test chamber where Wheatley makes an exit from another room, if you break his monitor before he pulls out the exit, it'll miss the animation and make the test impossible to solve.}}
 * Genre Savvy:
 * Wheatley {{spoiler|becomes Dangerously Genre Savvy in several ways after he takes control of the facility}}. He's still an idiot, though.
 * {{spoiler|1=After GLaDOS regains control of the facility she decides to let you go. Her reasoning is that she's sick of trying to kill you, and bad things happen to any AI that tries to kill you.}}
 * Aperture Science itself gets a nod: in the lower levels they have signs urging employees to watch out for OSHA inspectors and, later, instructing them to know their paradoxes in case of a rogue AI. Too bad you're mute and the AI in question isn't smart enough to see the paradox.
 * Getting Crap Past the Radar: The Adventure core you encounter during the boss battle says that he is a black belt in bedroom.
 * Giftedly Bad:
 * Under Cave Johnson, Aperture Science invented many remarkable products...that were all intended for completely different purposes. When used for their intended purpose, the products were generally fatal.
 * . For a moron actively ignoring how he's destroying the labs, he's surprisingly good at throwing curveballs at {{spoiler|1=GLaDOS and the player}}.
 * Gilligan Cut/Tempting Fate: This happens a lot. For example, {{spoiler|1=GLaDOS is sure she didn't prepare hundreds of tests in advance that Wheatley to steal and use. A minute later, it's revealed she kept hundreds of old tests.}}
 * During the Final Boss:
 * And shortly afterwards:
 * A God Am I: {{spoiler|1=Wheatley plays this trope out just about perfectly after being plugged into GLaDOS' mainframe. Justified in that there's some implication it may be programmed in such a way that any mind plugged into it becomes megalomanically insane, or at least obsessed with running experiments.}}
 * Good News, Bad News:
 * Gory Discretion Shot: The closest thing to violence in the game is obscured behind panels when it happens. {{spoiler|1=GLaDOS is "decapitated" during the core transfer, and sounds very much in pain.}}
 * Got Volunteered: The Lab Rat comic reveals that Chell was initially disqualified as a test subject due to her personality profile. Doug Rattmann altered her file to get her into the testing program. The rest is history.
 * Glowing Eyes of Doom:
 * GLaDOS has one when you awaken her for the first time.
 * When {{spoiler|1=Wheatley is plugged into GLaDOS's body}}, the walls glower at you with red light.
 * Gretzky Has the Ball: Wheatley informs you that he's holding all the cards... and they're all full houses.
 * Hand Wave: The reason why GLaDOS can't {{spoiler|give you any advice or hints in Chapter 8 is because she's programmed to be unable to give hints to test participants, otherwise she receives an electric shock. The writers added this because they needed a justification for why she wasn't giving you advice to clear the final few test chambers. Instead, this is used to set up a moment where she tricks Wheatley into giving you a hint for the puzzle you just solved, so he gets shocked.}}
 * Hannibal Lecture: GLaDOS delivers an absolutely caustic one in a piece of cut dialogue.
 * Happy Birthday to You: Changed to "For He's a Jolly Good Fellow", as par for the trope. GLaDOS hums the tune a few chambers prior to your "surprise", which just makes it that much creepier.
 * Hard Light: One of the new physics elements, platforms made of this can be redirected through portals and block turret fire, among other uses.
 * Heel Face Turn: {{spoiler|1=GLaDOS, of all people, after Wheatley goes mad with power and takes over the facility. Not that she had much of a choice, being a potato and all. Also a case of Enemy Mine.}}
 * Deadly Change-of-Heart: finally figures out he's sorry for trying to murder Chell {{spoiler|when he's stranded in space and, in all likelihood, will never get to say it to her face.}}
 * Hemisphere Bias: The shot of Earth is a NASA stock photo, showing North America. {{spoiler|Justified to the extent that the Aperture facility is in Cleveland (or Michigan), so a straight shot to the Moon would necessarily have you face that side of the planet. The position of the planet relative to the moon, however, is still off once you get there.}}
 * Heroic Mime: Chell, the main character. Lampshaded with frequency and gusto throughout the game. According to Word of God, Chell can talk. "She just chooses not to, what with the robots all being dicks. Why give them the satisfaction?"
 * When Wheatley is testing Chell for brain damage and asks for her to talk, the pop-up tutorial claims that pressing the jump button will make Chell speak. As always, it just makes her jump, much to Wheatley's confusion.
 * Wheatley then concludes that you are indeed brain-damaged.
 * In Chapter 4, Wheatley is contemplating a Big Red Button that might open a door. If you wait long enough, he will ask you for your opinion on the matter, and then engage in some epic navel gazing about the meaning of your lack of a response.
 * In Chapter 9, Wheatley mocks you about how you're so bossy, standing there in smug silence and various other ramblings.
 * GLaDOS mentions it yet again at the end of the game.
 * He Who Must Not Be Named: None of the personality cores seem to want to mention anybody else's names.
 * Chell is never addressed by name by anyone, period {{spoiler|except in the beginning of the turret opera, where a Multiple Reference Pun alludes to it}}. There is exactly one, easily missed place where it is written down.
 * There is unused dialogue in the game where GLaDOS does say Chell's name.
 * Wheatley never addresses GLaDOS by name within the game, only referring to "her" and "she".
 * In the same sense although not in the same way, GLaDOS never refers to Wheatley by his name. She only refers to "he", "him", and variations on "that little idiot".
 * There is exactly one exception: the Fact Sphere has some rather unkind things to say about the Space Sphere and the Adventure Sphere.
 * Hitler's Time Travel Exemption Act: A Dummied Out voice clip of Cave Johnson references this:
 * Hobos: When Aperture Science was falling on hard times, Cave started picking hobos off the streets for test subjects.
 * Hoist by His Own Petard:
 * GLaDOS insults Wheatley to get him mad... which works, but also causes him to {{spoiler|"install" her into a potato out of spite.}}
 * The Final Boss's bombs are used to help beat it, in a manner similar to the rockets from the first game.
 * Hollywood Darkness: Many unlit areas still have decent visibility due to the fact that the void of the facility seems to glow. There are two truly dark sections, once in Chapter 4 during "The Surprise", and one part in Chapter 5 during "The Escape". Oddly, in the latter case, as soon as the flashlight turns on, the ambient light does too.
 * Hope Spot:
 * At the conclusion of the Disc One Final Boss "fight". No, you didn't beat the game that easily, not even close. Sealed with the Wham! Line:
 * In the Old Aperture test shafts, you frequently find elevators to the surface. Sadly, they are all out of order.
 * How the Mighty Have Fallen: The entire Old Aperture sequence is designed to convey how this happened to Cave Johnson.
 * Hub Level: Co-op mode contains one of these. Initially only one area is accessible, but completing test chambers will result in new areas opening up.
 * Humans Are the Real Monsters:
 * From the co-op mode trailer.
 * And from the 'Bot Trust' trailer
 * Played with at the end, where P-Body {{spoiler|shoves Atlas into the fire, just like the humans did.}}
 * Ironically averted in co-op: GLaDOS muses that most humans aren't monsters, just good test subjects, determining the ratio to be about a million to one.
 * Human Popsicle: Ten thousand Enrichment Center test subjects were kept in storage this way, woken up automatically every fifty days to perform routine physical and mental maintenance exercises. In the years between Portal and Portal 2, all but Chell have apparently died of neglect.
 * However, the end of co-op reveals {{spoiler|that there are hundreds more humans in cryonic storage, waiting to be tested.}}
 * Humiliation Conga: {{spoiler|1=GLaDOS}} gets run through this. First you "kill" GLaDOS in the previous game, then  {{spoiler|you replaced the turret drones with useless defective ones just before she tried to kill you}}, then  {{spoiler|her supply of neurotoxin gets ruined}}, then  {{spoiler|she gets replaced with Wheatley}}, then  {{spoiler|she gets turned into a potato}} and after that  {{spoiler|the potato gets carried off by a bird that partially eats her and sticks her in its nest}}. It gets to the point that  {{spoiler|she eventually decides at the end that killing you is simply too much trouble and lets you go}}.
 * Hypocrisy Nod: {{spoiler|1=Wheatley, who is trying to figure out how GLaDOS gets you to finish tests, tries making fun of your weight and (possible) Parental Abandonment. GLaDOS, who had earlier thrown fat and adoption jokes at you with gusto, counters Wheatley's insults by asking what's wrong with being adopted, and pointing out that Chell isn't really fat. But then she says to Chell:}}
 * Hypocritical Humor: Much of GLaDOS's dialogue is spent telling Chell what a terrible person she is for killing her in the first game. It's not like GLaDOS has tried to do that or anything.
 * I Can't Believe It's Not Heroin!: {{spoiler|Wheatley seems to get high on watching Chell solve puzzles.}}
 * Idiot Ball: A literal example with {{spoiler|1=Wheatley, who is an actual ball designed to make GLaDOS dumber by generating an endless stream of stupid ideas to distract her. He does occasionally come up with a few good ideas, in a "broken clock is right twice a day" sort of way.}}
 * I Fell for Hours: After {{spoiler|Wheatley freaks out and knocks you down the elevator shaft}}, you find yourself falling for long enough to have a (rather one sided) conversation with GLaDOS about what Wheatley's true purpose is. She even lampshades it.
 * Ignored Epiphany: At the end of Portal 2, {{spoiler|1=GLaDOS says saving Chell triggered a surge of positive emotion...which allowed her to figure out where the source of those gooey human emotions was located in her memory banks, so she deletes it. Or so she says.}}
 * The Immodest Orgasm: What happens when Chell solves {{spoiler|Wheatley's}} first few tests. GLaDOS comes pretty close to it at the end of the co-op campaign too.
 * Can't forget GLaDOS moaning "Yeah!" and breathing heavily when {{spoiler|Cave Johnson is pissed about his imminent death and rants about burning down people's houses with lemons.}}
 * Incendiary Exponent: thinks that his mashy spike plates would be even better if he could figure out how to make them shoot fire. Fortunately he never gets around to it.
 * GLaDOS mentions that the light used to make hard light bridges comes directly from the sun, and that if you rubbed your cheek against one it would be like standing outside in the sunlight. And then your hair would catch fire, so you shouldn't actually do that.
 * Incompetence, Inc.: Aperture Science, oh so much.
 * Inconveniently-Placed Conveyor Belt: Used precisely once as part of a puzzle; you solve it with Propulsion Gel.
 * Individuality Is Illegal: Defective turrets get recycled. For Black Comedy, they are intelligent enough to know that they are defective.
 * Ineffectual Sympathetic Villain: {{spoiler|Wheatley.}} Indeed, his incompetence is quite literally the whole point of his existence.
 * Inferred Holocaust: Both explicitly and implicitly.
 * In addition to the countless Aperture Science personnel who were killed, Wheatley also mentions that besides Chell, there are at least 10000 other test subjects being kept in stasis, and they're most likely all dead.
 * At the end of the single-player campaign, {{spoiler|Chell is abandoned in a field of grain with nothing but a Companion Cube for company}}. Depending on how the world of Portal interacts with the Half Life universe, she could be very screwed. The humans presumably beat the Combine within that time, and they seem to have accomplished some rebuilding since the wheat field appears to have been actively cultivated, but who knows what else is going on? However, it's also inverted: since Earth's atmosphere is still breathable and there are still birds and plants, we can infer that the Combine was defeated before they managed to xenoform the planet.
 * Given Cave Johnson's progression from recruiting the "Best of the Best of the Best" as test subjects in the 50s to street bums in the late 60s and finally his own employees (and their children, no less) in the 80s, it's very strongly implied that most if not all of them died.
 * Wheatley tells you that the turrets are programmed to feel pain, of a sort. How good do you feel about all those turrets you knocked into pits, incinerated or carried through Emancipation fields now?
 * Chell's been continually exposed to the various toxic substances that Aperture Science created, especially during her sojourn in the old test chambers. How long is she going to last, really, after the game is over?
 * At the end of the co-op campaign {{spoiler|1=GLaDOS gets her hands on a huge supply of fresh human test subjects. After making it abundantly clear that as far as she's concerned, it isn't proper science if the test subjects don't die horribly.}}
 * In the "Peer Review" DLC {{spoiler|she says she's been trying to turn them into "killing machines", only to find that they were "far more fragile, and far vocal about how fragile they are" than "you-know-who". Now they're all dead.}} Bonus points for the fact that occurred in the span of one week.
 * Informed Ability: Wheatley is allegedly scientifically engineered to be {{spoiler|1=the world's biggest moron, and only come up with bad ideas. While he certainly isn't very bright, and has a lot of bad ideas, he also manages to outwit Chell and GLaDOS several times.}} Then again, he was Aperture Scientifically engineered, and they tend not to do things straight.
 * Ink Suit Actor: An odd, fan-based version. Fan-art depicting the AI characters as human is extremely common for the series, and Human-Wheatley is almost always drawn to resemble his voice actor Stephen Merchant.
 * Instant Cooldown: At the end of the game, {{spoiler|1=GLaDOS is able to bring the Enrichment Center's nuclear reactor back from the brink of a meltdown to full operational status.}} This is foreshadowed by the BSODs you see on the monitors as you go through {{spoiler|Wheatley's test chambers}} - all she had to do was press a key... metaphorically, anyway.
 * Insurmountable Waist-Height Fence: Broken rubble and panels not fully retracted are surprisingly able to block the player's movement. It's also impossible to jump over the catwalk railings, but a break in the railings almost always indicates where you do need to jump, or at least place a portal.
 * Inventional Wisdom: The old Aperture Science facility gives ample evidence of this principle being in effect; the most Squick-inducing being the Repulsion Gel, which was originally designed as a dietary aid that would make food bounce off of your digestive tract, and the Propulsion Gel, which speeds food through the body so quickly that it can't be digested.
 * Ironic Echo: At one point, Wheatley, prior to attempting to hack, remarks "Let the games begin." Later, {{spoiler|after you escape his deathtrap}}, he repeats it somewhat more menacingly. Of course, the menace is undercut by his highly nonthreatening villainy.
 * Cave Johnson asks Caroline to "Say goodbye, Caroline," and she humorously responds with "Goodbye, Caroline." At the end of the game, when GLaDOS (supposedly) {{spoiler|deletes Caroline from her brain}}, she repeats the line "Goodbye, Caroline" with a calm but malicious tone.
 * "Grab me! Grab me! Grab me!"
 * GLaDOS's insults to Chell about her being fat and abandoned by her parents at birth is repeated in a similar fashion in the Peer Review DLC. {{spoiler|1=GLaDOS "adopts" a group of baby birds, telling them that they are fat and were abandoned.}}
 * "I can still fix this!"
 * It's a Small World After All: {{spoiler|Wherever you aim your portal gun at when you shoot the moon, you'll end up at an Apollo landing site, despite the fact that there are only six Apollo sites on the entire near face of the moon (and only three with a Lunar Roving Vehicle, if you want to get specific about which site)}}
 * The Jimmy Hart Version: After entering {{spoiler|Old Aperture}}, a piece of music (titled {{spoiler|"Music of the Spheres"}} in the soundtrack) plays that is very obviously inspired by, and sounds a lot like, the famous prelude from Vertigo.
 * People have noted that Robots FTW, the ending theme to the Co-Op campaign, sounds suspiciously similar to BRODYQUEST.
 * I Want My Beloved to Be Happy: One of the most common interpretations for why {{spoiler|1=GlaDOS sent Chell away in the ending, based on the closing songs. Well, more "safe" than "happy", but same general concept.}}
 * Kick the Dog:
 * Know When to Fold'Em: {{spoiler|{{smallcaps|"Killing you? Is hard. So you know what? You win. Just go."}}}}
 * Landmark of Lore: The abandoned offices and enrichment spheres from the early days of Aperture Science.
 * Large Ham:
 * Wheatley has periodic bursts of ham, {{spoiler|1=mostly after he gets plugged into GLaDOS's mainframe.}}
 * Cave Johnson is about as hammy as a Bad Boss gets.
 * Late to the Party: Chell, waking up centuries after the Enrichment Center apparently stopped maintaining itself. Of course, this particular party is one she herself caused by destroying GLaDOS in the first game.
 * Leaning on the Fourth Wall:
 * The first thing Wheatley asks you to do once you let him in is to speak. When you jump instead, Wheatley assumes that you have indeed suffered brain damage, lampshading Chell's Heroic Mime status.
 * GLaDOS makes frequent references to Chell's weight, with one of her earlier comments expressing surprise that Chell has somehow gained a few pounds despite being in extended hibernation. Thing is, she's right. Compared to her earlier model in the original Portal, Chell doesn't look nearly as malnourished.
 * At the very end of the game, while {{spoiler|Wheatley is floating with Space Core in space}}, he says "The End". Cue the game going back to the menu.
 * Level Editor: Besides the Hammer-editor based programs available, a simplified in-game map maker was added in May 2012.
 * Level Goal: In some cases, very hard to find, especially in the old Aperture Science facilities and {{spoiler|Wheatley's test chambers}}.
 * Little-Known Facts: Emitted by the Fact Sphere.
 * Load-Bearing Boss: A rare and weird case of an inversion. You need to defeat the boss to stop him from blowing up the facility through negligence.
 * Loads and Loads of Loading: While hardly a bad offender, the loading screens are more noticeable than for the original game. It's much milder when actually in-game, however - loading a map from the main menu can take quite a while, but loading the same map from the one before it takes only about a tenth as long, as does loading auto/quicksaves from within the same map.
 * Logic Bomb: In the old Aperture Science facility, there's a poster on a wall listing various paradoxical statements in the event of a rogue AI. Too bad you're mute. {{spoiler|1=GLaDOS tries one against Wheatley, but he is literally Too Dumb to Fool.}}
 * And if you pay attention, the Logic Bomb actually works on the Frankenturrets. That should tell you something.
 * Logo Joke: During the earlier parts of the game, every loading screen shows an Aperture Laboratories logo. {{spoiler|Later, being knocked out of the modern areas, the logo changes to an older version, reading Aperture Science Innovators, and when you return to the modern Enrichment Center, the logo is defaced to read Wheatley Laboratories.}}
 * Lost in Transmission: The prerecorded message giving advice in the event that an Animal King has taken over Earth cuts out just as it's about to tell you what to do.
 * Luck-Based Mission: One of the achievements is for catching a Weighted Storage Cube in a particular test chamber before it touches the ground after being doused in Repulsion Gel. It's pure blind luck if the cube will even bounce in your direction to begin with.
 * Luke, I Am Your Father: Sort of. {{spoiler|One of the "Bring Your Daughter To Work Day" experiments is labeled with Chell's name and mentions a "special ingredient from Dad's work," implying that she's the daughter of a male scientist who is, or simply raises her with, an Aperture employee. Some players have speculated that Caroline was her mother, although making the timeline work requires invoking superscience or adoption, given their respective ages.}}
 * Lyrical Dissonance: "Want You Gone" is a happy, upbeat song about, well, Exactly What It Says on the Tin. Also a hallmark of the guy who wrote it.
 * Mad Science:
 * Once you get to the abandoned Test Spheres in Shaft Nine and find the remains of 50s-era Aperture, it becomes obvious this was the case in Cave Johnson's era, as nearly everything in this section of the game is gloriously lifted from 40s-50s-era pulp sci-fi.
 * In the co-op campaign, GLaDOS wonders if testing that isn't inherently deadly can even be considered science. Note that said testing would be deadly to humans, but she doesn't have any to run the courses.
 * Magic Countdown: The timer in the Final Boss fight. At the start, it's stated that you have six minutes before {{spoiler|the facility explodes}}, but each phase of the battle is independently timed regardless of how long you spent in the previous phase, giving you potentially as much as twelve minutes to work with. And that doesn't even count the Take Your Time that happens immediately afterward, and however long it takes {{spoiler|1=GLaDOS to fix the reactor after you win}}. It's an awfully forgiving six minutes.
 * Meaningful Echo: In the last 1950s recording, Cave says "Say goodbye, Caroline", and she good-naturedly responds "Goodbye, Caroline." Later on, after Cave's final recording (complete with hacking cough and him outright saying that he's going to die very soon), {{spoiler|1=GLaDOS says {{smallcaps|"Goodbye, sir"}} in an obviously sad tone of voice.}} Later, {{spoiler|1=when GLaDOS supposedly deletes Caroline, she says {{smallcaps|"Goodbye, Caroline"}} in a relatively neutral tone.}}
 * Meaningful Name: "Caroline" means {{spoiler|1="free woman"}}.
 * Metaphorgotten:
 * Cave Johnson's rant about life giving you lemons also counts. See Rage Against the Heavens.
 * Million-to-One Chance: Practically Lampshaded by GLaDOS, who applies "heavy rounding" to get your odds of success even that high.
 * Mind Hive: GLaDOS appears to be this—she claims to experience the personality cores as maddening, constantly babbling voices in her head. {{spoiler|After The Reveal, she becomes aware of Caroline's personality as "the voice of a conscience" within her mind as well.}}
 * The Mind Is a Plaything of the Body: {{spoiler|1=Both Wheatley and GLaDOS are significantly nicer (although they're still ultimately kind of jerks) when not plugged into the mainframe.}}
 * Mind Screw: Due to an entity the developers used to make level design easier, it's possible to get levels like this.
 * Minimalist Cast: Same as the first game. Just add a talkative British-accented personality sphere, two robots with no fear of death, and recordings of the... differently sane company founder.
 * Misapplied Phlebotinum: Aperture Science is built on this trope; it's their creed, and is emphasized much more in this game than in the first. See Inventional Wisdom.
 * Mission Control Is Off Its Meds: Again, but this time it's acting as Mission Control, or rather, trying to and failing. Badly.
 * Mistaken for Profound
 * Mobile Maze: There were hints of it in the original game, but Portal 2 demonstrates that most of Aperture Science is a giant facility full of moving parts capable of rearranging themselves. After some time has passed, the facility cleans itself up nicely.
 * Monster Is a Mommy: {{spoiler|The bird, whose nest you find at the end of the Peer Review DLC}}.
 * Mood Whiplash: {{spoiler|The otherwise somber stinger at the end of the game is pretty much ruined by the Space Core's squees of delight over finally being in space.}}
 * Depending on your point of view, Cave Johnson's last scene might count as well. His famous speech about the lemons, possibly the funniest moment in the game, is followed shortly by what for all intents and purposes is his last will and testament. {{spoiler|1=GLaDOS bidding him a resigned "Goodbye, sir" at the end is almost poignant}}.
 * In the last chapters of the game, the test chambers start featuring excursion funnels. Which wouldn't clash with the ambient mood {{spoiler|1=of desperate urgency (since the player has found out that Wheatley's negligence is going to result in a nuclear meltdown and every second probably counts) if the excursion funnel music didn't sound like this.}}
 * Morality Chip: This plot element from the first game is extended. GLaDOS (without the Morality Core) states that while she had heard voices from the Cores her entire life, she now hears {{spoiler|a conscience. And it is absolutely terrifying, because it is her own voice}}.
 * According to the trailers, the turrets have one. And another device to suppress it. Just because.
 * Morton's Fork:
 * {{spoiler|Once Wheatley takes control, Chell is left with a dilemma--team up to put the archnemesis she just defeated back in control (and begin their cycle all over again) or keep Wheatley in control and everybody blows up. But Thou Must! does not begin to describe it.}}
 * In a lighter example, GLaDOS dismisses suggestions of human testing subjects for 'less lethal tests', because they couldn't have been sure they were lethal if they survived to write the suggestions.
 * Motor Mouth:
 * Pretty much all the cores (save for the Morality and Anger Cores) are this, but Wheatley takes the cake. His entire dialogue in the game, played continuously, goes on for an hour and a half. GLaDOS is no slouch in this one either, though.
 * As stated above, Wheatley can actually {{spoiler|outtalk the destruction of the facility if you let him during the final-boss fight.}}
 * The Multiverse: The Perpetual Testing Initiative DLC is set up like this.
 * Mundane Made Awesome:
 * Cave Johnson won Best Curtain Rod Salesman of 1943, one of his greatest accomplishments.
 * Congratulations! You just opened up the entrance to the original facility. It even comes with flashing flood lights! {{spoiler|Wrong door. It's the tiny door behind the gigantic one.}}
 * Mundane Utility: The Portal Gun, a device so amazingly useful it would revolutionize the world—revolutionizing transport, providing inexhaustible power, breaking relativity—is used to test the efficacy of food additives, among other things. At least, they started out as food additives...
 * The Multiverse: The "plot" of the level-creator DLC revolves around it: Cave Johnson's been scamming the Multiverse by tricking them into building his test-blueprints, and you're sent bouncing around it solving them. Some of the parallel universes're...interesting.
 * Mythology Gag:
 * {{spoiler|There's an easily-overlooked doorway in the old portion of Aperture that leads to what appears to be a dry-dock that once housed the Borealis. The achievement you get for finding it calls it "the missing experiment".}}
 * {{spoiler|One of the humans frozen in cryogenic storage found in the ending to the Co-op game}} is listed as Adrian Sheperd. Make of that what you will.
 * A couple of cut ideas from the main game make it into parallel Universes in the level-editor DLC: the main Cave has an assistant called Greg, and in one Universe is a dead man put into a computer (as was the original plan for him before it got leaked.)
 * Never Recycle Your Schemes: Though in this case, it's more "never recycle your boss fight tactics." {{spoiler|1=GLaDOS dispenses with her previous boss fight tactics this time around, settling for just trapping and killing Chell, but this fails because Chell and Wheatley sabotaged the turrets and neurotoxin. When Wheatley becomes the main villain later, he looks over GLaDOS's tactics and revises them to make himself more formidable. He doesn't succeed, but he comes closer to killing Chell than GLaDOS did.}}
 * Never the Selves Shall Meet: Cave's message in one test chamber:
 * Never Trust a Trailer:
 * Only one test chamber from the trailers appears in the game, and it has differences. Although, it can still make sense since the footage came from a time when the game was in beta. It could have been an effort to not spoil the actual puzzles, but it would be nice if they included the chambers as a map pack later.
 * One feature for Portal 2 in the trailers, the "Pneumatic Diversity Vent," was never used at all (at least, not in any puzzles). In the trailer, Chell shoots a portal underneath a pneumatic tube to suck up turrets, loose wall tiles and other things. This proved too difficult to balance for gameplay purposes, so in the final game it only gets used for scripted scenes.
 * Highly pedantic, but this trailer implies that ATLAS and P-body both use blue/orange portals, when in actuality ATLAS uses blue/purple and P-body uses orange/red. Then again, they were both using an ordinary portal gun in that trailer.
 * Needless to say, if you were one who watched the trailers of GLaDOS reawakening, you were probably one of many who were freaked out when {{spoiler|claws descend from out of nowhere to grab you and Wheatley}}, since that part wasn't in said trailers. The dark atmosphere and music, also absent from the trailers, didn't help.
 * Nice Job Breaking It, Hero:
 * When you {{spoiler|1=replace GLaDOS with Wheatley, who goes crazy and whose stupidity ends up almost destroying the facility.}}
 * {{spoiler|1=And the co-op bots who help GLaDOS find the human test subjects, after she spent the entire campaign complaining that robots (and plants) are no good for her tests because they can't suffer or die.}}
 * Arguably done by {{spoiler|1=GLaDOS, since the reason she and Chell become trapped in the lowest levels of the Aperture facility is because she decided to taunt the power-mad Wheatley after she had just been transferred into a potato battery}}.
 * No Celebrities Were Harmed: Valve has more or less admitted that Cave Johnson is a mix of the crazy genius and need for showmanship of Nikola Tesla combined with the charisma and presentation skill of Ted Turner. The recorded announcements from the 1952 facility also strongly resemble the announcements Walt Disney recorded for the 1964 World's Fair (and Cave Johnson's {{spoiler|hopes for avoiding death by scanning his brain into a computer}} are reminiscent of Walt Disney's rumored {{spoiler|posthumous cryogenic preservation}}).
 * No Control Group: Averted with heavy parody:
 * No OSHA Compliance: Lampshaded here too.
 * There are signs in the 70s-era Aperture labs ordering employees to warn their superiors if they see several authorities, first among which are OSHA inspectors.
 * The unnamed male computer announcer tells you near the beginning that the safety measures for the test chambers have been deactivated to preserve reactor integrity. But testing will continue!
 * This mirrors what GLaDOS in the first game says about that very same test chamber:
 * At the beginning of the old test facility, and at the end after you leave, there are condemnation notices posted on the walls. These are dated 6/15/1961, but the dates painted on the Repulsion Gel and Conversion Gel facilities indicate that construction and testing were ongoing at least as recently as 1982.
 * Made more apparent by Cave Johnson being openly indifferent when it comes to participant safety:
 * Nostalgia Level: After the intro, the game starts by putting you back in the test chambers from the original, but overgrown and half ruined by the intervening years. You quickly diverge from that path, however.
 * And after you retrieve the dual portal gun from the incinerator, you walk through a narrow trench to the elevator. If you look around before getting in, you can see that you were actually backtracking the entire length of test chamber 19.
 * "Not Making This Up" Disclaimer: The description for the achievement "Lunacy" is simply "That just happened."
 * Not Rare Over There: Companion Cubes.
 * Not So Different:
 * Parodied in a scene that is in a trailer, and turned up as an unused line.
 * Also invoked in the game itself, specifically, the ending. {{spoiler|1=GLaDOS describes Caroline as being a lot like Chell (except not quite as heavy).}}
 * Notice This:
 * Sometimes if you dawdle for too long either GLaDOS or Wheatley will explicitly tell you not to look at something/touch something/perform some action. Naturally, that's your cue to look/touch/perform.
 * Parodied with the sign: "In case of implosion, look directly at implosion." This helps clue you in that it's your job to destroy the {{spoiler|neurotoxin generator}}, not Wheatley's.
 * "Not Wearing Pants" Dream:
 * Off the Rails: While the game itself is still completely linear, there's much more freedom to explore the environments, and, in-universe, large chunks of the game have you zig-zagging on and off the rails that various characters are trying to get you to follow. Chell's tendency to do this is apparently one of the reasons GLaDOS (and later {{spoiler|Wheatley}}) get so frustrated with her.
 * Oh Crap: From Wheatley, when he finds out you killed GLaDOS in the first game.
 * The defective turrets often say this.
 * Old Save Bonus: Some hats unlocked in Team Fortress 2 can be worn in the co-op mode of the PC version.
 * Omnidisciplinary Scientist: One of GLaDOS's put-downs involves her claiming an engineer, who purportedly noted Chell looks stupid in a jumpsuit, has one of these.
 * One-Scene Wonder: Despite only showing up {{spoiler|during the final boss fight}}, each of the defective Spheres have already gained a small cult following.
 * Only Sane Man: The alternate-universe Cave Johnson who's also in charge of Black Mesa is appalled by the dangerous science and pretty much calls everyone else out.
 * Order Versus Chaos: GLaDOS and Wheatley, respectively. {{spoiler|Both get to take their turns at being the good one and the evil one}}.
 * Origin Story: Chapters 5 through 7 take you (literally) deep into the origins of Aperture Science. Pre-recorded dialogue in Chapter 7 reveals that {{spoiler|1=GLaDOS was built as an attempt to achieve Immortality through Brain Uploading for Cave Johnson's secretary Caroline, whom he left in charge of Aperture Science after his death.}}
 * Override Command: Played with at the end of Chapter 1. Wheatley is trying to stop GLaDOS from reactivating, but since he doesn't know the code, he starts brute-forcing it.
 * Parodied in the final boss battle where Wheatley, in an effort to stop the meltdown, may correctly guess the correct password. He promptly deletes the Emergency Heat Venting Protocols. This also says something about Aperture's passwording tendencies.
 * Parrot Exposition: See Department of Redundancy Department.
 * Password Slot Machine: Played with; see Override Command. Bonus points for Wheatley's eye spinning whilst inputting passwords.
 * Becomes a Brick Joke at the end of the game. Needing to hack another password, he doesn't bother being sequential and guesses randomly... which actually produces the right password. He's quite pleased at his first successful hack.
 * People Jars: The "Relaxation Chambers," one of which houses Chell up until the start of the game. The co-op mode explores this element further.
 * Percussive Maintenance / When All You Have Is a Hammer: Wheatley's solution to a stubbornly unhelpful wall, and a window on a locked door.
 * Playing the Player: During the escape sequence. {{spoiler|1=GLaDOS offers to facilitate your escape by quickly creating a puzzle room. It's a trap, of course, but you've been playing so long by that point you might have a case of lab rat mentality and just waltz right in.}} You even get an achievement, just for the devs to rub it in.
 * Better yet: {{spoiler|Later on, Wheatley makes it very obvious that after the last test chamber, he's got a nasty surprise in store for you (of the murderous variety). Then, two chambers before that, the game sets up a simple Aerial Faith Plate puzzle...where the Plate unexpectedly flings you sideways, and Wheatley decides to hand you the surprise a few chambers early.}}
 * Point of No Return: Every test chamber door and elevator is a one-way trip. Those that aren't are uniformly part of a puzzle.
 * Pointy-Haired Boss: Cave Johnson, big time.
 * The Power of Love: {{spoiler|The solution to the final puzzle of the co-op campaign requires you to use a gesture, as the vault lock looks for proof of the person opening it being human.}}
 * Pragmatic Villainy:
 * Some of the signs in the ancient bowels of Aperture Science tell test subjects to be careful because lawsuits are expensive, replacements hard to come by, and investigations bad for business. There are also signs instructing employees to notify a supervisor in the event they spot an undercover police officer or OSHA inspector, and offering Logic Bombs in case of a rogue AI.
 * {{spoiler|1=GLaDOS}} at the end of the single-player campaign.
 * Preorder Bonus: In the Steam preorder you get a free copy of Portal, in case you didn't already have it (or if you do, you get a giftable copy).
 * There were also different in-game ones for Steam preorders as well as regional Gamestop and Amazon preorders.
 * Let's not forget the Play Station 3 version coming with a free Steam copy.
 * Press X to Die: At one point, an obvious trap shows up and Wheatley warns you about it. You can still fall for it if you want.
 * Near the end of the game, {{spoiler|Wheatley}} simply asks you to get crushed by nearby, easily avoidable machinery.
 * Professor Guinea Pig: Cave Johnson had no qualms about testing his inventions on himself. This of course led to his death by Conversion Gel poisoning. In fact, by the end of the 80s, Aperture Science was bankrupt and couldn't recruit test subjects, so it began testing all of its products on its own employees, with a corresponding negative effect on retention.
 * Public Domain Soundtrack: The 'classical music' Wheatley plays is J.S. Bach's Little Prelude in C Minor (BWV 934).
 * Pulling Themselves Together: The game puts on a visual showcase by having the entire Enrichment Center do this after GLaDOS wakes up. The scene where she is reactivated was in one of the trailers used to sell the game.
 * Punctuated Pounding: {{spoiler|1=Done when Wheatley smashes you and GLaDOS into a pit after GLaDOS pisses him off.}}
 * Punny Name: One of the alternate Cave Johnsons from the PeTI DLC is referred to as "Dark Cave".
 * Rage Against the Heavens: Cave Johnson has one of these in one of his last pre-recorded public messages, after he found out he'd been poisoned by ingesting moon dust. GLaDOS's reaction doesn't help either.
 * Ragnarok Proofing: The Enrichment Centre is capable of testing even in the event of an apocalyptic scenario, and contains helpful pre-recorded messages detailing how different varieties of apocalypse might affect testing. The place is pretty wrecked though, which initially looks like an aversion of the trope, but once power is restored, GLaDOS is able to repair and rebuild it, at least superficially, in a matter of hours.
 * Railroading: A lovely little lampshade in the game opening: “No rail to tell us where to go! This is brilliant. We can go wherever we want! Just hold on, where are we going, seriously. Hang let me just get my bearings. Umm, just follow the rail, actually.”
 * Real Life Writes the Plot:
 * Caroline (and all her accompanying backstory) was added to the sequel because they needed a character to play off of Cave Johnson, but they didn't want to hire a new voice actor for one or two lines.
 * All dialogue related to cake was deliberately removed from the game because the Portal team were so sick of hearing about it. There are at least two brief visual references, though: there's a drawing of GLaDOS taunting Chell with it near the first portal gun, and {{spoiler|1=the fake door that GLaDOS uses to trap Chell says, "GLaDOS emergency shutdown and cake dispensary"}}.
 * Realistic Diction Is Unrealistic: All the characters with dialogue are either AI's, presumably with plenty of processor power devoted to proper diction, or speaking through prerecorded messages. This is actively averted, however, by Wheatley, whose colloquial and Buffy-Speak-laden dialogue is intended to come across as very "human" and personable—except when he's trying to sound smart or confident.
 * "The Reason You Suck" Speech: {{spoiler|Wheatley}} gives one in the final battle. {{spoiler|One of his complaints includes not catching him when he dislodged himself from the railing at the very beginning of the game. Not even trying. What makes it even more amusing is that you can't, no matter how hard you try. The "use" key won't grab him until he's hit the ground.}}
 * Redemption Equals Death: Parodied with the Turret Redemption Line for defective turrets. You can guess exactly where it leads to.
 * Red Eyes, Take Warning: The turrets. {{spoiler|Averted in the ending cutscene though.}}
 * In a slightly different scenario, just as {{spoiler|Wheatley goes power-crazy, his normally-blue}} eye briefly turns yellow. Anybody who knows the color of GLaDOS's eye knows immediately that something bad has just happened.
 * Reed Richards Is Useless: Just one of Aperture's inventions would have revolutionized the world, if only they'd figured out how to sell them properly (and make them safe).
 * Replacement Goldfish: {{spoiler|1=When the prototype control system for the Enrichment Center is taken over by GLaDOS' most hated enemy, she tries to train the humans from the co-op ending to be killers like Chell. Turns out normal humans are not nearly as durable nor so reserved about mortal peril.}}
 * Required Secondary Gadgetry: The Long Fall Boots in the second game are elaborated on in the fourth Aperture Investment Opportunity video. Cave Johnson goes into great detail explaining how the boots are designed to prevent the easily reproducible human error problem of falling from great heights and damaging expensive equipment.
 * Restraining Bolt: Similarly to the Morality Core from the first game, {{spoiler|1=Wheatley was made to suppress GLaDOS' intelligence.}} There are also several restraining bolts hardcoded into the Aperture Science mainframe: one forces the AI to conduct tests and stimulates a euphoric response to subjects completing a test; the response diminishes in intensity over time as the AI builds up a resistance, as mentioned above. Another zaps the controlling AI if it tries to give hints. Yet a third apparently prevents the AI from reconfiguring the mainframe chamber to eliminate the manual core replacement apparatus.
 * Retcon: Much of Cave Johnson's backstory is changed from the info that was released at the time of the original Portal. Instead of dying as a result of mercury poisoning, he now became sick as a result of ingesting Conversion Gel, although that part could be blamed on Johnson being an Unreliable Narrator. In the old story, he proposed the idea for the portal gun while he was on his death bed. However, in Portal 2, all of the test chambers {{spoiler|in the original levels of the facility}} require the use of a portal gun, even the ones that were constructed when Johnson was still young.
 * Due to the staff who made Portal being sick to death of "The Cake Is a Lie", all of the bottom-right corner images of cake in the original test chambers you see in Portal 2 are gone completely, replaced with an image of a person above two rotating crusher columns.
 * Retraux: The '50s and '70s versions of the Aperture Science logo fit well with those eras' design aesthetics.
 * Roaring Rampage of Revenge: What you and {{spoiler|1=GLaDOS}} are on at the end of the game.
 * Robo Speak: GLaDOS' voice here is somewhere between the sexy croon at the end of Portal and her original, very computerized voice. It gets more tinny after she gets {{spoiler|stuck in the potato}}. All the other voices, except for those of the original turrets that carry over, are an aversion.
 * The developer's commentary states that Valve intentionally made the smartest AIs sound the most robotic, so that Wheatley, the dumbest character in the game (or ever) sounds the most human and personable. Casting him with a British accent was part of this, as according to their audience research, Americans associate a British accent with being smart. To Britons, however, Stephen Merchant has a West country accent, usually associated with being pleasant but not too bright. Which is basically exactly what Wheatley is.
 * Rule of Perception: {{spoiler|When you shoot a portal to the moon at the end, you see a Twinkle in The Sky shortly after the shot hits, as portal effects travel at the speed of light; it takes 1.4 seconds for the shot to get there, and 1.4 seconds for the twinkle get back. However, nothing starts getting sucked through the portal into the vacuum of space until shortly after you see the twinkle - presumably, the formation of the portal connection itself also propagates at the speed of light.}}
 * Running Gag:
 * (Claims of) Chell being adopted and unwanted.
 * Chell's supposed weight issues.
 * Wheatley being told he would die if he did any number of things.
 * Wheatley's rather pathetic attempts at hacking.
 * The defective turrets.
 * Turrets falling into various implements of destruction, such as incinerators and crushers.
 * GLaDOS calling Wheatley a moron.
 * The (apparently singular) bird that continually harasses the AI characters. First mentioned in passing by Wheatley as part of a Noodle Incident Hand Wave about his survival, it appears three more times in the main game and once again in the DLC.
 * Samus Is a Girl: In-universe example—Wheatley passively assumed that whoever took GLaDOS out was a male test subject before GLaDOS revives and reveals that it was Chell.
 * Sarcastic Clapping: GLaDOS has a processor to generate this, which makes it into {{spoiler|her potato form.}}
 * Sarcasm Mode:
 * A Call Back to the first game; this is literally one of the first things GLaDOS re-enables when she powers herself back up.
 * Wheatley nearly forfeits at a critical moment when the supervisory program fails to understand his sarcasm.
 * Say It with Hearts: During your second escape, GLaDOS opens up a testing chamber that she claims is the "last one". The wall panels flip to make a vertically oriented <3 sign. It's not a good idea to trust her.
 * Of course, there is an achievement for falling into the trap, aptly named "Good Listener", followed promptly by a reload. If you're playing in Challenge Mode, she not only tricks you with the room, but also a fake finish line as well, which disappears when you touch it.
 * Say My Name: Averted, Chell, GLaDOS and Wheatley presumably all know each others' names, but only Wheatley's is ever spoken out loud (By himself).
 * Scenery Gorn:
 * At the beginning of the game, most of the Enrichment Center is in ruins and overgrown by plants, although it gets repaired eventually.
 * The first walk through GLaDOS's chamber is designed to show off her ruined body.
 * The entrance to Old Aperture is similarly impressive, particularly the giant Enrichment Spheres secured in the air and the giant door sealing off the testing area.
 * The final testing environments have openings revealing a seemingly endless panorama of test chambers, which crumble and collapse the closer you get to the end.
 * Schizo-Tech/Decade Dissonance: Invoked intentionally, the middle third of the game takes place in a section of Aperture Science that had been sealed off sometime in the sixties or seventies. You go from Twenty Minutes Into the Future to offices filled with typewriters, punch-card computers and rotary telephones.
 * Schmuck Bait:
 * "GLaDOS Emergency Shutdown and Cake Dispensary -- Keep Unlocked"
 * Also, GLaDOS' last test chamber, and the bottomless pit that {{spoiler|Wheatley}} tells you to jump in after you escape the deathtrap. Falling for these gets you achievements.
 * In one of the test chambers, GLaDOS tells Chell not to take anything with her due to a missing Emancipation Grill. Of course, she wants you to attempt it so she can taunt you some more. You get an achievement for it, too.
 * While Chell is carrying him across a seemingly bottomless pit, Wheatley tells her not to look down. She doesn't respond, naturally, but he immediately falls for it. Twice.
 * Schrödinger's Cat:
 * The Lab Rat comic has GLaDOS mention she's running her own tests on cats, and it gets a few nods in the game itself as well. Symbolically, in the comic Rattmann compares Chell to the cat; simultaneously alive (sleeping in stasis) and dead (she may never be revived).
 * Also implied by the Fact Core:
 * The Science Collaboration Points Mean Nothing
 * Science Is Bad: They have even more fun with the trope than in the first game, with Cave Johnson angrily telling an employee who asked if the tests could be a bit safer to invent a safe door that won't hit his butt on the way out, cause he's fired. And of course there's GLaDOS who openly questions if the co-op tests with robots who can't die or feel pain is really "science". Aperture just seems to have its own definition of the practices it actually refers to.
 * Screens Are Cameras: Wheatley appears to be able to see through several of the video screens dotting various parts of the facility. In fact, there are a couple of parts where he reacts in pain to any of them being damaged. He later becomes jumpy whenever a flying cube almost hits them.
 * Self-Destruct Mechanism: Helpfully provided as a backup in case a nuclear meltdown is imminent but you don't know when it will happen.
 * Sequel Escalation: The first game was so short, it was practically a proof-of-concept demo that got by with a unique mechanic and hilarious writing. The second is full-length, and include loads of new features, including co-op.
 * Sequence Breaking: It is possible {{spoiler|1=to skip meeting GLaDOS and make it to the elevator in the lower level. She just appears on your portal gun without explanation in the next scene.}}
 * Because the co-op levels are unlocked based on the player with the most experience, it is possible for a first time-player to complete the final level before doing any others. Consequently, said player will then have every other chamber unlocked regardless of who they play with, since they have registered progress in the last chamber.
 * Shapeshifter Baggage: The Scaling Cube from the Sixense DLC has this problem. Adjusting its size increases its mass. Thus, a normally harmless cube can be made into a giant slab capable of crushing turrets like bugs.
 * Shoot the Television: Late in the story, the player can use the portal gun and the in-game momentum mechanics to hurl objects (or oneself) at monitors on which Wheatley appears. Destroying them all earns the player an achievement/trophy.
 * Shout-Out: See Portal (series)/Shout Out.
 * Shown Their Work:
 * The Enrichment Center is in fact part of a much larger complex of factories and testing facilities located in a gargantuan cave network built out of what was originally salt mines near and under Cleveland, Ohio, that Johnson acquired in the 1940s. While the scale of the caves in the game are... a bit exaggerated, the Cleveland salt mines are a completely real thing. Oddly, the game itself Retcons the mines to be located in Michigan, and there were never any salt mines there.
 * There is exactly one salt mine in Michigan, located about 1200 feet beneath Detroit. Interestingly, salt-mining in Detroit began before European explorers ever set foot on what is now Michigan soil. VALVe's retcon, however, locates the salt mine in Michigan's upper peninsula, which in real life has iron, copper, and a few gold mines, but no salt mines.
 * The speed of light is approximately 300,000 kilometers per second. Portal effects travel at around the speed of light. {{spoiler|It takes just under 1.4 seconds for light to reach the Moon}}. Do the Final Boss fight and get a stopwatch ready. Note that this almost fell victim to Reality Is Unrealistic before Valve figured out how to sell it. A Twinkle in the Sky is not so realistic, but used for Rule of Perception.
 * The area you shoot the final portal at is {{spoiler|near the Apollo 15 moon landing.}}
 * Shut UP, Hannibal: During the {{spoiler|Wheatley tests}} and ensuing escape, there are multiple opportunities to cut off some {{spoiler|of his rants by smashing something (sometimes yourself) into the giant screen he broadcasts from.}} It can be rather satisfying, and earns you an achievement if you get enough of them.
 * Skyscraper City: GLaDOS's chamber is the epicenter of Aperture Science, and a place of prosperity and ambition. Naturally, this being a science fiction game, it is balanced on a rather thin pillar overlooking an enormous precipice despite it's importance.
 * Slept Through the Apocalypse: Again.
 * Slapstick: Cooperative mode is pretty much made of this, at least for players with a loose definition of "cooperative."
 * Smashing Hallway Traps of Doom: "That's a crusher. We sell them too." These are found in some of the old Aperture Science areas, and {{spoiler|Wheatley}} becomes rather fond of them later.
 * Some of My Best Friends Are X: {{spoiler|1=When Wheatley makes an attempt at insulting Chell, he relies on GLaDOS' method of calling her fat and adopted. When GLaDOS messes with him by asking what's wrong with being adopted, Wheatley, after failing to come up with a good reason, falls back on this stock phrase.}}
 * {{spoiler|1=Space Is Cold/Explosive Decompression: Averted. The Moon's practically non-existent atmosphere may as well be the hard vacuum of space and, defying common storytelling wisdom, Chell survives the short while it takes for GLaDOS to save her. Justified, as she's right near a stream of Earth atmosphere flowing out to space, and she's only in space for around 20 seconds (permanent damage in a vacuum for humans only starts after 90 seconds).}}
 * {{spoiler|Space Is Noisy: You can hear Wheatley (and the Space Core) during the last scene. May be justified earlier, since air comes through the portal.}}
 * Spanner in the Works: According to GLaDOS, Chell is this. The Lab Rat tie-in comic makes this explicit; she was initially disqualified as a potential test subject due to nearly pathological tenacity (99th-plus percentile).
 * Spikes of Doom: {{spoiler|Wheatley}} becomes quite fond of crushers with spikes on them later in the game, and eventually wants them to shoot fire. They also appear in the co-op mode.
 * Spiritual Successor: The student game TAG : The Power of Paint heavily inspired the Repulsion, Propulsion, and Conversion Gels. In fact, the entire dev team for that game was hired by Valve in order to use their tech.
 * Springs Springs Everywhere: Aerial Faith Plates. Fortunately, unlike for the initial test subjects, they've been recalibrated not to send you into space.
 * Stealth Insult: GLaDOS drops these all the time while she tests you. The first time she does it, she refers to a bunch of garbage as being smelly and useless, and then clarifies that she was actually talking about you and she was afraid you didn't get it because you didn't say anything.
 * Later, when you fling yourself around a test chamber a few times:
 * Stealth Pun: Valve said that the voice of Wheatley would be provided by, in their words, "Some guy from the office". Originally it really was: the placeholder voice was provided by Valve animator Richard Lord. Then they chose Stephen Merchant, most well known for his appearance on UK sitcoms The Office and "Extras".
 * {{spoiler|It gets better. What did Richard Lord say about his replacement? He was "over the moon" with excitement. Guess where Wheatley winds up?}} (This may end up to be just a coincidence though, considering how much the story was progressed at that point.)
 * {{spoiler|During the ending turret opera scene, a rather round turret leads the ensemble in soprano. Shortly after she's done, the game ends.}} So, in other words, it ain't over til' the fat turret sings.
 * Hard Light Bridges are made of sunlight taken from the surface. In effect, whenever you use them, you're literally Walking On Sunshine.
 * When Cave Johnson makes his infamous rant to "take back Life's Lemons", he mentions how he will get his engineers to invent an "Combustible Lemon" to burn down Life's house down with. An exploding lemon could also be called a lemon grenade. In other words, Cave Johnson takes lemons and makes Lemon 'nades.
 * The Fact Sphere gives one if you're lucky enough to hear it:
 * All personality spheres are roughly the same size. In the end, {{spoiler|the space sphere is orbiting Wheatley; therefore, Wheatley is incredibly "dense".}}
 * When Chell is beaten and thoroughly defeated, with her adversary holding all the cards, as it were,her only option is a very risky Desperation Attack: she literally {{spoiler|shoots the moon.}}
 * The Stinger: The game takes this and runs with it, delivering no less than three stingers throughout the ending.
 * Stock Sound Effect: {{smallcaps|You know, it's a fact that people with a guilty conscience are more easily startled by sudden loud nois-}} *TRAIN HORN* {{smallcaps|I'm sorry, I don't know why that went off.}}
 * Stupid Statement Dance Mix: The potato song (warning: minor spoiler)
 * Stupidity Is the Only Option: Played straight, where the only option available is to fall for GLaDOS' trap. She even says she had prepared better traps for you when you got past this one, which doesn't make sense since there is literally no exit out of the room you're in except the trap. Lampshaded later on by GLaDOS when she remarks that the chamber you're about to enter is undoubtedly a trap but there's no other option. Also see But Thou Must!.
 * Stylistic Suck: {{spoiler|Wheatley's poorly designed test chambers}} are intentionally invoked Scrappy Levels used to portray  {{spoiler|Wheatley's poor intelligence, his naivety and how the Enrichment Centre has fallen into disarray under his control}}. The developer commentary states that they tried to make these chambers look as if they were created by first-time level designers, right to the corny idea of "signing the scenery with huge words."
 * Surprise Jump: Referenced.
 * Suspiciously Specific Denial: Wheatley requests this of Chell should his superiors come calling.
 * Tactical Suicide Boss: {{spoiler|1=Wheatley with his bombs. To his credit, he has bomb-proof shields ready since learning from the fight with GLaDOS, but there aren't enough to completely shield him and he didn't take Conversion Gel into account. Like GLaDOS, he also can't shut the bombs off.}}
 * Take That:
 * People got very attached to the Companion Cube in the first game. In one of the early test chambers, GLaDOS decides to have fun by taking that fact into consideration. Multiple times.
 * The test chambers designed by {{spoiler|Wheatley}} are pure Stylistic Suck - they all either consist of empty rooms with a single button that opens the exit straight away, have death traps that lack the "death" part ({{spoiler|Wheatley}} even apologizes for not knowing how to fill the "deadly moat" with water, though if you didn't have long-fall boots, that easily-avoided fall would be at least crippling), have words crudely spelled out on the wall out of the level elements, or they're levels designed by {{spoiler|1=GLaDOS}} crudely glued together with a few extra elements - sometimes just cosmetic - thrown in. Now look at any depository of player-made maps of any given videogame featuring user-created content. On a good day, only 75% will fit this mold.
 * Cut dialogue from the co-op mode has GLaDOS assign ATLAS and P-body to recover some human artifacts, including what sounds like a Garfield strip. Her evaluation of its content is not kind.
 * Testosterone Poisoning: The Adventure Sphere!
 * There Is No Kill Like Overkill: In {{spoiler|The Part Where He Kills You}}, one imagines that the sheer quantity of mashy spike plates weren't entirely necessary. Two or three would have worked just fine.
 * This Is Sparta:
 * This Is the Part Where: {{spoiler|Wheatley Kills You.}}
 * "Three Laws"-Compliant: Well, they know of the Three Laws.
 * Tomato in the Mirror: {{spoiler|1=In Old Aperture, GLaDOS learns that Caroline, Cave Johnson's assistant, was uploaded into her. For all her antagonism towards humans, she is at least partially human herself.}}
 * Too Dumb to Fool: {{spoiler|Wheatley}}, who is immune to Logic Bombs thanks to being too stupid to understand the concept of a paradox. (See Too Dumb to Live.)
 * Too Dumb to Live:
 * Astonishingly played in reverse! {{spoiler|Wheatley's}} inherent stupidity gives him immunity to paradoxical statements that would fry any other AI. Leave it to Valve to find a way to play Too Dumb To Kill. On the other hand, {{spoiler|he does sit on top of the facility as the reactor is about to explode}}.
 * Collectively, all of Aperture Science's personnel. Specifically, the ones who thought it would be a good idea to empower a potentially malevolent AI to release a deadly neurotoxin. Cave Johnson, the founder, gets his own version by testing the effects of human consumption of Conversion Gel on himself.
 * Too Spicy for Yog-Sothoth: By the end of the game, {{spoiler|1=GLaDOS is so sick and tired of Chell repeatedly killing her and wrecking the Enrichment Center that she finally allows her to leave the complex.}}
 * Trailers Always Spoil: You knew GLaDOS was going to come back. It was inevitable. You also know that Wheatley isn't dead after you meet GLaDOS and that GLaDOS' defeat isn't the end of the game.
 * Trap Door: From floors that collapse due to structural decay to glass ceilings that shatter under your weight to actual trap doors and walls.
 * Trap Is the Only Option:
 * Lampshaded when {{spoiler|Wheatley}} crashes a room into a walkway you're using. GLaDOS points out that it's a trap, but you can't go anywhere else.
 * The Booby Trap on the {{spoiler|Stalemate Resolution Button}} is clearly obvious if you look closely enough. Again, though, you have no choice.
 * Trust-Building Blunder: In the "Bot Trust" promotional video. Hey, the robots lasted six seconds longer than the human test subjects—go science! Earlier in the video, ATLAS directs a blindfolded P-Body to navigate around an Aerial Faith Plate, with predictable results.
 * Truth in Television: Moon dust is, indeed, "pure poison" (somewhat akin to asbestos dust), and will prove a challenge to overcome if we ever get around to attempting to colonize it.
 * Tsundere: GLaDOS {{spoiler|finally lets you go, but only because it's the easiest way to never have to see your stupid fat face again and totally not because she likes you or anything, okay?}}
 * In the ending song {{spoiler|"Want You Gone", she insists at length that she's happy and relieved to be rid of Chell, and mocks the idea that she might have considered Chell a friend...until near the end of the last verse, when there's a single line implying she misses Chell. This line appears as "[REDACTED]" in the lyrics displayed onscreen.}}
 * A Twinkle in the Sky: Happens when a portal gun is shot very far. In this case, {{spoiler|the Moon}}.
 * Understatement: GLaDOS is prone to this:
 * Twitchy Eye: After Wheatley is damaged in the first encounter with GLaDOS, he has a short circuit that causes him to spark and jerk randomly. Since he looks like a robot eyeball, the net effect is strongly evocative of a twitchy eye in a human, and serves the same purpose in terms of Foreshadowing.
 * Unexplained Recovery:
 * Apparently, the {{spoiler|Weighted Companion Cube}} from the first game was never properly incinerated, as it reappears without explanation (albeit a little charred) at the end. See Brick Joke.
 * Wheatley is crushed "dead" by GLaDOS when she wakes up. A few test chambers later he reappears more or less intact, save for a shorted circuit that sparks every now and then, with a Noodle Incident Hand Wave about a bird that the player only gets to hear part of. Said bird becomes a Running Gag as well as a Brick Joke.
 * Unnecessarily Large Interior: In the first game, you thought the Enrichment Center was quite big. In the second game...you find out that the Enrichment Center is big. Really big. And was built atop the old Enrichment Center.
 * Which is even bigger... and the part of it you go through in the game is only one of at least nine equally large areas according to the map near the beginning of it.
 * Unreliable Narrator: While GLaDOS certainly was one through the events of the first game, in the sequel it gets so crazy that it even goes so far as to extend to {{spoiler|the operational history of Aperture itself -- Aperture Science Innovators was running crazy superscience experiments, complete with some form of backpack-powered portal device, as early as the 1950s, when the "official" history says all they did was make shower curtains during this time and that the concept for the portal device didn't even come up until after Cave Johnson was "poisoned" in the 70s. Even the original given founding date is proven wrong, as signs in Shaft Nine proudly proclaim Aperture began science ventures in 1947, rather than 1953... the latter of which is the date when original portal testing began. Johnson's own recordings, naturally, also include pretty much his own take on everything.}}
 * {{spoiler|It's possible the official history is right as well; Johnson seemed to think the portal technology had some sort of application in the shower curtain sector.}}
 * Variable Mix: The music changes briefly when utilizing the various elements in each test chamber.
 * Vestigial Empire: While not an empire per se, the sealed-off test chambers (along with Cave Johnson's portraits) visualize both Aperture Science and their founder's deteriorating prestige and wealth over the years. In the fifties, they were testing astronauts, Olympian athletes and war heroes. By the seventies, they were paying homeless people and Johnson mentions he's gone bankrupt. By the time Johnson became deathly ill in the eighties, they were forcing employees to become test subjects.
 * Vetinari Job Security: GLaDOS is hardly the nicest individual ever... but {{spoiler|Wheatley's attempt to run the facility is a disaster, and you end up putting Aperture back in her hands because she's the only one who can run it effectively; significant, even if you disapprove of the testing, since part of the facility is a nuclear reactor well on its way to detonating due to Wheatley's neglect}}.
 * Video Game Caring Potential: The game lets you rescue a moping, defective turret from the incinerator. It gives you a very honest "thank you" and an achievement titled "No hard feelings". In co-op, you can give hugs to your partner...
 * Video Game Cruelty Potential: ...but also refuse them. Part of the reason for using robots for co-op is so players wouldn't feel bad about killing each other in hilarious ways. And that defective turret above? Yeah, you can stick it into an Emancipation Grill immediately afterward, if you're feeling evil.
 * Villainous Breakdown: The entirety of Chapters 8 and 9 can be seen as an extended version of this, but the payoff occurs during the Final Boss battle. Best exemplified in the penultimate line below.
 * Violation of Common Sense: Two specific achievements require you to take actions that will result in your immediate death. No, not your probable death. No, not your death only if you aren't quick enough on the portal triggers. To get those achievements, you must knowingly and willfully commit actions that will lead to your doom.
 * GLaDOS even comments on one of them. If you sit around long enough listening to {{spoiler|Wheatley's attempts to coax you into jumping into a pit}}, she'll suggest that you really do have brain damage to actually be considering it.
 * Co-op has a variation on this: you have to knowingly and willingly commit an action which leads to your partner's death. More conventionally, finding the hidden Companion Cube is a one-way trip, but you don't know that going in.
 * Visual Pun: {{spoiler|During the ending where the turrets sing an opera piece, a rotund turret sings soprano.}} In other words, it's over when the fat turret sings.
 * The holes that Atlas and P-Body fall through in the co-op first-time intro, as well as the new Vital Apparatus Vent openings? They're apertures.
 * Twice in the old test areas, you must do a Portal Fling jump. When you do, you fly or head through a huge Aperture Science sign hanging in the room, through the round "Aperture" logo.
 * Waif Prophet: The "I'm different" turret.
 * The Walls Are Closing In: GLaDOS closes all four walls around the player in one Death Trap, only they're not used to crush the player but to force the player to stand over a Trap Door as part of a larger trap.
 * And since the walls are comprised of smaller, independently moving panels, she even makes them creep forward in alternating progression as though they were large creatures crawling forward.
 * The Walls Have Eyes: The panels that make the walls of testing chambers have a glowing eye on the arms that hold/assemble them. It can get rather off-putting when the entire side of a room ratchets up and rows of teal pinpricks aim at you. It gets terrifying when the lights turn red.
 * We Have Reserves:
 * On completion of the Co-op Multiplayer mode, Atlas, P-body, and GLaDOS discover the {{spoiler|cryofrozen bodies of the ten thousand other test subjects.}}
 * GLaDOS claims that there are entire warehouses filled with spare companion cubes.
 * Weird Moon: The Moon in this game is significantly larger than in real life. Might come in handy...
 * Wham Level: There's Chapter Five, {{spoiler|which includes the somewhat predictable but still-heavy wham of Wheatley losing it when plugged into the mainframe}}, and then things get really heavy in Chapter Six, {{spoiler|wherein it's revealed that Aperture's superscience programs, including the portal device, are much older than everyone originally thought...}}
 * Also in easter egg form, we have the {{spoiler|Borealis Dry Dock.}} Which hints that  {{spoiler|it may have been used for teleportation experiments}}
 * Wham! Line: "Actually... {{spoiler|Why do we have to leave right now?}}" If the Evil Laugh preceeding it didn't do it, that line is what really clues you in to the fact that {{spoiler|1=plugging Wheatley into GLaDOS's body}} was not the best idea.
 * What Happened to the Mouse?: Cores besides Wheatley in general. The cores that woke up at the end of Portal are never mentioned again (besides Wheatley), unless the bin of defective cores is meant to be the same thing. Wheatley mentions a manufacturing foreman (and at least one copy of him, so likely a core), but this is never touched upon. It also makes GLaDOS being "still alive" that much more confusing (her presumed backups being irrelevant), as it turns out she really was dead, more or less. The commentary indicates that there were originally going to be six distinct cores, but they were either cut and/or recycled as defective cores at the end of the game.
 * What Measure Is a Non-Human?: The reason why the co-op characters are robots instead of humans, so their many deaths are Comedic Sociopathy rather than shocking.
 * Played with all over the place, even in the first game with GLaDOS's ending song, but especially so in the sequel with repeated mentions of turrets not feeling pain (maybe), and eventually culminating with {{spoiler|1=GLaDOS being a specialty AI based on a previously living person}}
 * Even Wheatley seems amused when unpleasant things happen to turrets, despite mentioning in passing that they do feel pain. It's okay if it is "simulated" apparantly.
 * According to GLaDOS, even the Companion Cubes are sentient. Though given the relationship players form with the little things, there's a fairly high chance she's trolling.
 * What the Hell, Player?: Portal 2 contains a surprising amount of dialogue that you can't hear unless you do something that requires a conscious act of stupidity.
 * Dying in the HUB in co-op really confuses GLaDOS.
 * {{spoiler|After escaping Wheatley's death trap at the start of Chapter 8, you're free to answer his pleads for you to turn around and come back. He's naturally surprised and asks you to please jump in that bottomless pit over there, following it up with a list of various incentives. If you stick around long enough to hear him out...}}
 * When Life Gives You Lemons: Played straight and then later subverted by Cave Johnson (see the quote under Rage Against the Heavens).
 * White and Grey Morality: Shows this by the end. {{spoiler|1=GlaDOS undergoes some character development and not only lets Chell go but seems to appreciate her as a friend (though it's hard to tell), and Wheatley was always just an idiot who went drunk with power and in the stinger expresses regret for everything he did. No one is really "evil" any more.}}
 * Who's Laughing Now?: Most of what {{spoiler|Wheatley}} does after  {{spoiler|1=he gets plugged into GLaDOS.}}
 * Who Wants to Live Forever?: Averted. GLaDOS thinks living forever is just peachy, and repeatedly taunts Chell over the measly sixty or so years she has left.
 * Pure Intelligence Cave Johnson from the PeTI DLC finds it overwhelmingly boring. After reading the entire literary canon of all mankind in an instant, he proceeds to "improving" it by merging Ghostbusters with everything, before finally deciding he needs to kill everyone so he can ascend to Olympus.
 * Why Don't You Marry It?: Cave Johnson taunts his critics this way.
 * This also doubles as a Call Back to one of GLaDOS's lines from the first game:
 * Why Won't You Die?: {{spoiler|Wheatley's}} penultimate complaint about Chell, wholly justified at this point by her canonical Determinator status. Lampshaded lightly by GLaDOS as well.
 * William Telling: One trailer has Atlas attempting to shoot an apple off P-body's head... with a foot wide laser beam.
 * With Great Power Comes Great Insanity: See A.I. Is a Crapshoot above.
 * Worlds Smallest Violin: GLaDOS does a variation in co-op. When you complete one of the early tests, she notes that no one was supposed to have completed it, and promises to build the world's smallest trophy for you.
 * Worth It: GLaDOS after tricking Wheatley into zapping himself.
 * Xanatos Gambit: {{spoiler|Wheatley}} goes out of his way to anticipate every possible point of failure during the Final Boss fight. Being an idiot, he misses some key elements, but what elevates it to a Xanatos Gambit—and his crowning moment of being Dangerously Genre Savvy—is that he is just smart enough to anticipate the possibility that Chell could win. The only things that stop him from being victorious are Chell's status as a Determinator and a Chekhov's Gun he could not possibly have known about.
 * Yank the Dog's Chain:
 * Occurs in chapter 2. GLaDOS invokes it when the player tries to pick up (and use) the {{spoiler|Companion Cube}}. Twice.  {{spoiler|1=And unlike the first game you can save it. Then GLaDOS destroys it anyway. Then the original one turns up again at the ending.}}
 * In the old testing facility, you keep running into signs pointing to elevators that lead straight up to the surface. Every single one is either broken or inaccessible. Later, you do find an accessible shaft and ascend it, with a payoff at the end in the form of another of those giant doors. Opening it reveals a brilliant light... which is just a floodlight illuminating yet another elevator shaft.
 * You Are Fat: GLaDOS never actually calls Chell fat, but is very fond of implying it:
 * More so in the lines that did not make into the game:
 * Subverted when {{spoiler|Wheatley tries it}}, and GLaDOS contradicts him. It looks like Character Development, but her subsequent whisper to you indicates that she's just doing it to mess with him.
 * During the Final Boss battle, {{spoiler|Wheatley}} manages to work it in a bit more smoothly.
 * And lastly, during the credits song with "She was a lot like you (maybe not quite as heavy)".
 * Co-op mode includes an Expospeak Gag revolving around this, with GLaDOS telling the robots that the best way to insult a human is to '{{smallcaps|tell them that their weight variance is above or below the norm}}'.
 * You Can't Thwart Stage One: Try as you may, you can't prevent GLaDOS' reactivation. Or {{spoiler|Wheatley taking over}}.
 * You Have Got to Be Kidding Me!:
 * You Wake Up in a Room: This time, Chell wakes up in a "Relaxation Chamber". There are also two Callbacks to the Relaxation Vault from the first game; you jump down into the one from the first game when reentering the original test chambers, and GLaDOS later {{spoiler|traps you in one just before you confront her}}.
 * You Monster!:
 * GLaDOS utters this to Chell after waking up, despite the fact that GLaDOS is far more villainous. For bonus points, the Achievement for this scene is named "You Monster".
 * Also implied in co-op, the first time you blow up the turrets:
 * Your Head Asplode: According to Aperture Science, giving your lover chocolates for Valentine's Day will result in this scenario.
 * Your Princess Is in Another Castle: This one seems to end a little too quickly: {{spoiler|1=You install Wheatley as the new central core, deposing GLaDOS.}} Everything's sunshine and puppies, right? WRONG. {{spoiler|1=Wheatley proceeds to go mad with power and GLaDOS's insults provoke him into a rage, causing him to dump you down into the very deepest, most forgotten levels of Aperture Science... where the game's biggest revelations yet await Chell and the player.}}
 * Zero Effort Boss: GLaDOS, in Chapter 5. There isn't even a fight, just a very simple puzzle. Of course, it's not the end of the game...

{{reflist}} {{BAFTA Best Game}}