Advancing Boss of Doom: After "You" call the lift from the basement to trap the "Daddy" in the basement, it relentlessly pursues you through the basement until you escape.
After Action Report: After the credits, you will see your "psych report" and see statistics throughout the play-through.
All Just a Dream: In the original cut of the game, dying causes You to wake up as if he had just had a nightmare. This has been removed in The Director's Cut. Also, "You" are insane and spend several days in psychiatric care, regressed into your own mind throughout the game until the end.
All There in the Script: The Man in Blue has No Name Given, but the game refers to him internally as Draco. The name "Draco" is mentioned in the game as the author of a diary. In it, he describes his aggressive approach to survival (which serves as a tutorial for killing monsters). Two of the pages of this diary can be found in Apartment 206, where You lives. There is also an old note to be found in Apartment 205 that warns the reader not to listen to him. Although given how much this game relies on the Shrug of God, this probably doesn't prove it to be canon.
Badass Grandpa: The Director, who's at least middle-aged and routinely goes scavenging in the monster-ravaged wasteland for goodies.
Badass Finger Snap: The Man in Blue warps around and triggers music with a snap of his finger, like Star Trek's Q.
Badass Preacher: The Man Who Wears a Box is decked out in black clothing, advocates pacifism, and has a Christian cross scribbled on his headgear.
Big Bad: The closest thing to one is the Man in Blue, who tempts and taunts You into staying trapped in his delusions. He supplies You with extra ammo, encouraging aggression and destructive behavior. Mother could also be considered this, seeing as it is implied she is the source of the disease.
Big Eater: Your character is always complaining he's hungry.
Big Good: The closest thing to one is the Man Who Wears a Box. He supplies You with food and batteries, encouraging pacifism and healthy behavior.
Bland-Name Product: The GameJoy. The red-and-white soda can labeled 'soda'. The ground meat which is apparently called "SPUM". The GameJoy is changed to the ESP in the PS3/Vita versions and looks like a PSP.
Body Horror: The two types of monsters seem to be formerly humans, faceless and mutated.
Boom, Headshot: Thinmen-type mutants are most easily killed using this method. Due to the way aiming mechanics work, though, you need to be almost point-blank before you can shoot directly at the head, so be cautious.
Boss Battle: The only boss battle is at the end when scaring off "Mother".
Some might also consider "Daddy" a boss, even though you can only run from him.
Broken Bridge: The city and apartments would be a lot easier to navigate if these weren't all over the place.
Coat, Hat, Mask: The Director is easily identified by his shabby brown trenchcoat and fedora.
Companion Cube: The Cat Plush and Chuck the Plant. Curiously, talking to Sleepy Cat lowers your sanity, while talking to Chuck does not.
Cryptic Conversation: Expect a lot of this. The Director and Hank are the only ones who really bother to speak plainly.
Dead Weight: Fatmen. In keeping with gaming tradition, they take a lot more punishment than Thinmen.
Dramatic Unmask: If the player obtains the Green ending, it is assumed that "You" is actually the "Man who Wears a Box", but now without the box.
Driven to Madness: Occurs gradually to the protagonist (maybe), as well as Hank if he is given enough blue pills.
Does Not Like Shoes: An interesting example, as the protagonist only goes barefoot because, according to him, shoes make sneaking past the thin men much harder.
Evil Old Folks: An old man wearing a blue shirt is the biggest threat in this game.
The Man Who Wears a Box is the cuddly, pacifistic cousin of Pyramid Head. Additionally, the pocket flashlight and static could be a homage to Silent Hill.
Foreshadowing: The White-Faced Man is the main representative of the Green ending (as well as the Man Who Wears a Box), which shows the Lone Survivor the truth he's been trying to avoid. For that reason, the Survivor feels deeply uncomfortable whenever he draws near the pale-faced man.
Gainax Ending: In three basic variations: Red, Blue, and Green, with Yellow and White added to The Director's Cut. It's no coincidence that the Red, Green and Blue paths are named for the colors of pills you find lying around.
Girl Next Door: Hinted at to a degree. Several apartments on "You's" floor suggest the enigmatic and possibly metaphorical depiction of You's deceased lover, "Girl in Blue Dress" to have resided nearby.
Golden Ending: The Green Ending is the most difficult ending to get, as it requires you to keep your sanity relatively high by the end of the game, which means avoiding shortcuts that would make the game shorter/easier and doing more of the sidequests. The Green Ending is the only one that suggests you've recovered from insanity.
That description also applies to the White Ending, but more so. It requires you to max out your sanity and missing out on the New Game+ only sanity boosting items can screw you out of getting it.
Guide Dang It: You're more than likely to never find the cooking pot, receive the bonus item from The Director, or tame Sunny the cat through your first play-through without some outside assistance.
Home Sweet Home: "You" says "Home again." whenever you enter your apartment.
Hope Spot: A few. Most notably when after you survive the dangers in complete darkness you come into a serene, quiet, and well-lit area, you come to the girl hunched over under a ray of light. When you approach and try to speak to her, she says "I don't want you to see me like this" and, if your sanity isn't high enough, turns into a monster.
Horror Hunger: If you have very low mental health, attempting to eat rotten meat has "You" remark that it looks tasty. Also giving blue pills to the infected hank can result in him having hunger for meat.
Kleptomaniac Hero: Weirdly inverted. "You" is often, almost irrationally, concerned about not pilfering supplies from apartment 206 — almost to the point where it appears that he's angry with himself for even considering it. However, he has no problem taking objects found in the other rooms (scissors, keys, etc) or searching their closets. It might be acertained that he only takes things that are required for his survival.
Money to Throw Away: When given the option to rifle through a cash register for cash, "You" remarks to himself how useless currency is.
Last Lousy Point: Attempts to obtain a more preferable ending are bound to be dogged by this.
Limited Wardrobe: "You" refuses to take/wear the clothing that is found in his apartment (the shoes and jacket are particularly noteworthy), instead opting to go several days (or weeks) wearing the same outfit.
Loners Are Freaks: Averted by The Man who Wears a Box. He's a bit of a weirdo and tries to convince the Survivor that isolation prevents you from being hurt, but is ultimately one of the more benevolent characters.
Luke, I Am Your Father: A radio snippet right at the game's end suggests that this may be the case for You and The Director.
Magic Mirror: Mirrors can inexplicably serve as a gateway between Apartment 206 and distant locations. You can only have your apartment mirror attuned to the most recent mirror you looked at, but it's easily the fastest and least dangerous way to get from point A to point B. It surprises "You" the first time it happens, but afterwards he takes it in stride.
Morality Pet: Available in the form of an actual pet, a stray white cat that you can adopt if you feed it enough cans of cat food. Feeding it and petting it improves your sanity, taking away some of the black marks you may have earned though killing things.
Multiple Endings: The ending that occurs is based on numerous acts performed in the game. These statistics are listed as a "psych report" after the ending is shown.
Murder Makes You Crazy: Literally. Killing monsters is a fine way to lower your sanity. If you want to avoid that happening, get used to sneaking around and using flares.
Nightmare Dreams: The game opens with one of Your night terrors—although to be honest, it's actually not much scarier or dreamlike than the waking parts of the game.
No Name Given: Most characters have either vague names (You and She), descriptive ones (White-Faced Man, the Director), or actual ones (Hank, Chie), but the Man in Blue's title is only shown in the postgame; otherwise, his name shows up as "???" or "Seated Figure" even though he constantly insists that You knows him. This might be because he's actually a hostile figment of You's imagination. If You acknowledges that he's real, it earns a ton of points towards the Blue ending.
No Peripheral Vision: Some rooms have alcoves that "You" can press against to hide from and sneak past monsters.
Now, Where Was I Going Again?: Managed by means of the radio in Apartment 206. Scanning across all channels will give you a hint about what your current objective is.
Obi-Wan Moment: The Director is killed by Mother at the end of the game, directing the player to locate the hospital and lamenting the loss of someone dear before finally succumbing to his wounds and expiring.
Retraux: Everything is done in a highly pixelated style.
The Plague: The monsters are created this way. Hank has been infected, and is slowly turning into one himself. He can be cured if the player gives up all the rare health potions found in the last act of the game.
Sanity Meter: Albeit an unseen one that affects which ending you get. Several factors raise or lower your sanity, including monsters killed, types of foods/pills consumed, sleep schedule, and the completion of optional sidequests.
Attempting to eat Rotten Meat acts as a visible indicator of You's sanity. If You's mental health is fine, You will just say "No." If it's deteriorating, "Maybe." If you've been neglecting it a lot, "Actually, that looks pretty tasty."
Mirrors are another indicator. "I'm doing well, considering" is good. "I'm starting to look like one of them" is awful.
Seeking Sanctuary: "YOU" has to take a Green Pill and go to sleep in order to visit The Man Who Wears a Box, who is dressed like a Padre. He provides you with some snacks/batteries should you run low on either.
Spoiled By The Soundtrack: The titles of some of the songs tell you a bit about the game that might not otherwise be clear. The ending music for the Red and Blue endings is titled "Sleep Forever". The title of of the Green ending theme is "Survival." The credits music for any ending is "Moving On." See where this is going?
Surreal Horror: What isn't symbolic is likelier just nonsensical, but often used to disturbing effect.
Survival Horror: This is the game's core mechanic, emphasizing resource management and difficult pick-your-battles scenarios.
Survivors Guilt: Arguably the driving theme of the game's plot. The Lone Survivor was in all likelihood the only one who lived through the bus bombing, and the events of the game itself are just an extended delusion to help him cope. The ending you get determines if he sinks further into psychosis, kills himself, or heals and moves on.
Talkative Loon: If given multiple blue pills, Hank will become increasingly unstable, sometimes just muttering to himself if prompted.
Ten-Second Flashlight: "You"'s flashlight is a real battery hog. Thankfully it's not necessary that often.
Through the Eyes of Madness: Deciding what's real and what isn't is largely up to the player. The game itself keeps its cards close to the chest.
Tomato in the Mirror: In the Green Ending, "You" turns into the Man Who Wears A Box, sans box. In the Blue and Red Endings, he turns into The Man in Blue.
Trademark Favorite Food: You has generally positive opinions on most of the things he eats, but cooked ham practically sends him into spasms of joy. Even the psych report listing for how many times you've eaten the dish just says "BAKED HAM!"
Two Roads Before You: TMWWAB is a pacifist entity, and seems to stand in polarity with the intractable aggression of The Man in Blue. While the man in blue provides ammo for your handgun, which in turn promotes a violent and destructive playstyle, the "Man Who Wears a Box" provides batteries and food, which promotes a peaceful and pacifist playstyle.
Weakened by the Light: While your dim flashlight will only attract their attention, the bright light of a burning flare will stun mutants, allowing you to dash past them unharmed. Enough flares can even drive off Mother, meaning you don't need to shoot her.
Hank has a strong aversion towards light (likely due to his infection) and will ask "You" to shut off the flashlight in his presence.
Weapon of Choice: The protagonist comes to a gun shop filled with automatic weaponry and even (somewhat inexplicably) a chainsaw. His statement that his pistol is more "his style" prohibits the player from picking up any of it.
The player hopes this is simply a case of Awesome, but Impractical being employed, as shotguns are very noisy and could potentially attract all manner of monstrosities towards you.
However, because the pistol itself is fairly loud anyway and doesn't come with a silencer, its truly a moment of Too Dumb to Live. Your character is intentionally snubbing weapons that increase his chances of survival.
Womb Level: A few areas in the game, like the Basement, look like they are this, but they actually aren't. This is intentional.
Violation of Common Sense: Even "You" says that sticking his hand in the Maw is crazy. But that's where the generator key is, so...
You Have to Believe Me: "You" can have a conversation like this with the guys at Chie's party. In their defense, "You" might actually be delusional on top of being hysterical.