[[quoteright:335:http://static.tvtropes.org/pmwiki/pub/images/Penumbra01140507.jpg]][[caption-width-right:330:[[GenreBlindness You know, he really should consider looking]] [[EnemyRisingBehind behind his back]]...]]

->''My name is Philip. If we are lucky, then by the time you receive this, [[PosthumousNarration I will be dead.]] If fate frowns, we all perish.''
-->--'''Philip [[HowWeGotHere during the intro]]'''

Spanning two games and an expansion pack[[note]]''Overture'', ''Black Plague'' and ''Requiem'' respectively[[/note]], '''''Penumbra''''' is a SurvivalHorror series that follows [[NonActionGuy physics professor]] Philip [=LaFresque=], who, after attending to his mother's funeral, receives a letter from his long dead father Howard instructing him to [[SchmuckBait destroy a breadcrumb trail of mysterious documents without reading them]]. Phillip, suffering from severe GenreBlindness, instead follows the trail to a forgotten old mine somewhere in [[MysteriousAntarctica northern Greenland]], where he promptly finds himself trapped and [[ParanoiaFuel (seemingly)]] alone during a blizzard.

Created by {{Creator/Frictional Games}} (the company that went on to make the equally terrifying ''VideoGame/AmnesiaTheDarkDescent'') Penumbra is also notable for its unique engine that allows solving puzzles through clicking, dragging, and directly interacting when using items, giving an especially genuine, immersive atmosphere that even earned ''Black Plague'' a nomination for best script (from The Writers Guild of Great Britain, that it ultimately lost to ''{{Overlord}})''.

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!!This series provides examples of:
* AbandonedMine: Primary setting for the first game.
* AbsurdlySpaciousSewer: A level in ''Requiem'' identifies itself as a sewer, and it has two side rooms with manholes at the top, a side room containing a generator and some transport system, and a large reservoir that you need to flood to progress to the next area. The water seems to be purified, unusual for a sewer. It follows the style meant for technical or experimental work.
* AfterlifeAntechamber: [[spoiler: ''Requiem'' seems to be this. Logs from Eloff Carpenter and Dr. Eminess indicate they both showed up in the labyrinth right after ''you know'' they died and they have no idea how they got there.]]
* AirVentPassageway: Used at the beginning and towards the end of ''Black Plague''.
* AllJustADream: The good ending in [[spoiler:''Requiem'']] is an example of this.
** Either that, or it's the bad ending, as [[spoiler: the Tuurngait trap Philip's mind in an eternal loop of his adventure, [[AndIMustScream which he must suffer through forever, unable to die.]]]]
* AllMythsAreTrue: There's a grain of truth in all the Inuit legends about the Tuurngait, mysterious spirits roaming the frozen wastes of northern Greenland...as you'll discover with alarming frequency from the occasionally found textbook or old newspaper article. Overlaps quite a bit with {{Foreshadowing}}.
* AnAesop: [[spoiler:[[SpaceWhaleAesop Work together or alien hiveminds will kill you in Greenland?]]]] An {{anvilicious}} aesop, considering the [[spoiler:Tuurgait come right out and make you jump through morality hoops and encourage your selflessness]]. Unless you consider the end of ''Black Plague'' to be positive. Then it's just a [[BrokenAesop broken one]].
* [[spoiler:AncientAstronauts: One possible explanation on how the Tuurngait came to Earth millions of years ago - ''"before man was even upright"''.]]
* AncientTradition / AncientConspiracy: [[spoiler:The Archaic, a secret society attempting to research the Tuurngait and mainly getting itself slaughtered. They're extremely corrupt, and willing to sacrifice the lives of lower-ranking members to protect the upper echelons.]]
* ApocalypticLog: Over and over - this is a horror game, after all. First with Dr. Roberts' (the spider hater) insane diary, then with Eloff Carpenter (who recorded on cassette his horrifying final moments) and at last, [[spoiler: with Philip himself]].
* ArsonMurderAndJaywalking: While in the infirmary, you stumble across a note detailing when using the Cryo-stasis chamber is deemed acceptable. The list of permissible ailments include "cardiomyopathy, glaucoma, polio, diabetes, or halitosis (bad breath)."
* BadassBookworm: Philip is definitely a NonActionGuy, but even he has his occasional moments of badassery.
* {{Backtracking}}: There is some, but fortunately, it doesn't take too long and tries to avoid becoming {{Filler}}.
* BagOfSpilling: Justified both times.
* [[spoiler:BizarreAlienBiology / StarfishAliens: The Tuurngait are apparently some sort of sentient semi-parasitic virus from an unknown world. They also have the traditional HiveMind element to them and are capable of altering the genetic structure and nervous system of other living beings.]]
* BaitAndSwitch: At the start of Overture the player keeps finding [[ApocalypticLog journal entries]] about [[spoiler:giant spiders and finding giant webs]] scattered around caves and tunnels and is then [[spoiler:attacked by zombie dogs.]]
* BetterToDieThanBeKilled: A rather hard to find (and [[DoorStopper Door Stopping]]) note in the UV light room talks of a scientist from the Shelter who read research papers on the Rock Worms.
** [[spoiler: At the end, it says that he tied a noose. "Those monsters may feed on my corpse, but they won't take my life."]]
* BittersweetEnding: The ending of ''Black Plague''. [[spoiler:Philip is doomed and everyone else in the complex is dead, but Philip manages to send a message to the outside world that will hopefully cause the Tuurngait to be destroyed.]]
* BlackComedy: Clarence embodies this trope readily.
* BodyHorror: There's a reason why everyone in the [[spoiler:Archaic]] has a CyanidePill - in case it would come in handy... [[spoiler:The infected has their skin take on a nasty color, it looks like part of their intestines were ripped out and attached to their genitalia, and [[ArsonMurderAndJaywalking they go bald among other things.]]]]
* BookcasePassage: Drawing a specific book from a bookcase in ''Black Plague'' will reveal a hidden room.
* BookEnds: [[spoiler:The email at the beginning of ''Overture'' is also the EpilogueLetter in ''Black Plague''.]]
* BrokenRecord: In ''Requiem'', a tape player gets stuck in a playback loop on a short phrase, despite it being empty. Later, the PA suffers from the same issue, and the announcer thanks you for fixing it before continuing with the intended message.
* ChekhovsGun: Armstrong's Mixture, to some extent in ''Overture.'' Shows up as a page in an explosives manual you find very early in the game but isn't actually used until very near the end where you use it to blow your way through to Red.
* ChunkySalsaRule
* {{Cloudcuckoolander}} / TalkativeLoon: Tom Redwood, a.k.a. [[EveryoneCallsHimBarkeep "Red"]]. He constantly insults, amuses and helps you in ''Overture''. All ''[[MissionControlISOffItsMeds at the same time]]''. He's both an unusual guide and a very memorable character, to say the least. When you finally manage to reach him, you have to [[spoiler:unwillingly partake in [[DrivenToSuicide a rather gruesome]] TwistEnding]]. After that you finally discover the secrets of Red's past and explore the isolated and squalid living spaces he had to occupy ''[[spoiler:[[TheAloner for thirty extremely lonely years]] ]]''. Cue TearJerker. No wonder the poor sap [[SanitySlippage went gradually insane.]]
** Subverted terryfyingly with Dr. Richard Eminiss in ''Black Plague''. He first seems to follow these tropes, but quickly [[TheReveal turns out to be]] [[OurZombiesAreDifferent anything but humorous...]]
* ConcealingCanvas: An AirVentPassageway is hidden behind an odd painting in ''Black Plague''.
* ContrivedCoincidence: How Philip managed to get into an abandoned mine which was exactly where he would find the secret research station where his father worked.
* CowardlyLion: If Philip so much as looks at a monster for too long, there'll be a [[FalseCameraEffects lens flare]], and he'll freak out and give away his position. That said, he never gives up, and he thinks and fights his way out of situations that kill everyone around him.)
* {{Cult}}: [[spoiler:The Archaic Elevated Caste again, though they deny it. They don't seem to be explicitly religious in any way, lack any sort of unifying symbol and have few official rites, etc. They're more like a secular, MadScientist version of this.]]
* DarkAndTroubledPast: Implied for [[spoiler:Philip]] and his [[spoiler:father, Howard,]] the latter requesting that several cryptic documents be destroyed. These letters contain the directions to the Greenland Mine in which the horrible events of ''Overture'' occur.
* DarknessEqualsDeath: The Kennels in ''Black Plague'', [[MemeticMutation in which you are likely to be]] [[VideoGame/{{Zork}} eaten by a grue]]. A major part of the puzzle there is manipulating the malfunctioning electrical lighting to allow Philip to pass otherwise dangerous zones safely.
* DeadpanSnarker: Clarence is extremely GenreSavvy in ''Black Plague'' and leaves loads of condescending comments on the plot development.
* DieChairDie: Generally averted. In the first two games, this is to your benefit, since often you'll need that chair to barricade the door against whatever is pounding it down. That said, there are plenty of breakables in the form of ketchup bottles, Scotch bottles, etc.
* DiegeticInterface: Besides the inventory window (default key TAB) and an optional tiny crosshair, there is basically no HUD at all.
* DissonantSerenity: Early on in ''Overture,'' you'll find the logs of a man who made a habit of studying and devouring the local spiders. You'll find an equally cheerful log not much later about how he had [[spoiler: [[BodyHorror to remove his own tongue after he realized it absorbed too many spider toxins]].]]
* DoorToBefore: The chemical labs have an emergency door, which you can open by sabotaging the flow of chemicals in the lab itself, but only after you get past cameras, enemies, and security puzzles. And then there's the matter of going through the hallway the door leads to...
* EnemyWithin: [[spoiler:Clarence, the Tuurngait's personal representative within your skull. He spends half of ''Black Plague'' trying to kill you and the other half trying to keep you alive [[{{Synchronization}} so he doesn't die too]]. It ''really'' doesn't help that he can give you hallucinations at will.]]
* EvilHasABadSenseOfHumor: [[spoiler:After Clarence tricks Phillip into killing Dr. Swanson, he jokes about a piece of her skull being on his shoe.]]
* TheFaceless: Every normal human who isn't already dead when you encounter them.
* FauxDeath / FakingTheDead: Gets you into the Archaic's [[HumanPopsicle cryogenics facility]] so you can steal one of the heads and [[BorrowedBiometricBypass use it to pass a retinal scanner]].
* FetchQuest: Done throughout (they ''are'' Adventure games, after all), and lampshaded in Black Plague.
-->'''Clarence:''' "Christ! Go here, go there, fetch this, run me a bath... typical broad, atypical circumstances."
-->'''Red:''' "Really, the hunger is becoming... rather uncomfortable here... How far away are you? You cannnot be far. I am held captive by a wall of stone in the northeast of the mine. As in any drama, there are many roles to be played. You must act the scientist in mixing potions, act the renegade in plots of destruction..."
*** In other words, you need to make an improvised explosive and blast through the cave-in separating you from the part of the mine inhabited by Red.
* FightingFromTheInside: [[spoiler:Each person who contracts TheVirus goes through a BattleInTheCenterOfTheMind, and almost everyone loses and becomes one of the Infected. Red, a CloudCuckooLander miner in ''Overture'', managed to win and retain partial self-control. In the second game, you go through such a fight yourself, with a win meaning you just have to put up with Clarence. Howard apparently managed it as well, but he was DrivenToSuicide.]] Dr. Eminess seemed to have won, but once you give him a saw, that's clearly not true.
* FindTheCure: Justified for once - [[spoiler:The Tuurngait [[YouWillBeAssimilated doesn't just want you dead]].]]
* FirstPersonGhost: That must be a pretty long glowstick for you to not see Phillip's hand.
* ForScience: [[spoiler:The Archaic, as already hinted at in the Cult trope entry.]]
* FramingDevice: The first two games are framed around an email from Philip to an unspecified individual, explaining why he failed to do something that needed to be done, and has to ask another to complete the task. What exactly he's talking about isn't fully explained until the end of ''Black Plague''. The expansion pack takes place immediately after.
* FreewareGame: The original [[http://www.frictionalgames.com/site/penumbra tech demo]] that started it all (it was created for a Swedish game development contest). The whole series is practically a ContinuityReboot and AdaptationExpansion of the tech demo's basic plot.
* FromBadToWorse: In the first game, your only enemies were rabid dogs, large spiders, and the occasional mutant worm. The enemies of the next game... [[EldritchAbomination are much worse]].
* FullFrontalAssault: The Infected.
* GiantSpider: In any other game, they'd be GoddamnBats. In ''Overture'', they're still weaker than everything else you encounter. Thankfully, they're not actually gigantic - just a bit overgrown.
* GenreBusting: It's an [[AdventureGame Adventure]] SurvivalHorror StealthBasedGame, with all the in-game manipulation controls and motions being based on dynamic real time physics...
* GrailInTheGarbage: One of the artefacts in ''Black Plague'' is located in a trash bin.
* GreyAndGrayMorality: The final choice Philip is presented with in ''Black Plague''. If he had [[spoiler:done as the Tuurngait wanted and asked the reader to remove all evidence of the Shelter, the Tuurngait, who seem a little too eager to assimilate the "invaders", would stay alive, likely indefinitely, and the Shelter would become a second tomb for the Tuurngait]]. When he [[spoiler: asks the reader to have the Tuurngait destroyed, he is killing off an ancient and wise being older than man that sowed pieces of its knowledge into our species]].
* TheGuardsMustBeCrazy: An Infected isolated [[spoiler: from the rest of the Tuurngait]] is generally not very bright.
* HealThyself: Painkillers. For that matter, [[WalkItOff just walking around in circles]] can bring you from "I can't feel my arms and legs" to "I'm as fit as can be expected" pretty quickly. File it under AcceptableBreaksFromReality, given how fast your HP can go back down.
* {{Hellhound}}: The first enemy type in ''Overture''. They're rather quick, and their HP is so high some walkthroughs mistake them for {{Invincible Minor Mook}}s, but they can't jump too high, and they're [[TheDevTeamThinksOfEverything easily distracted with a piece of beef jerky]].
* HeroicMime: Lampshaded by Clarence right as he comes into existence after Philip's out-of-body experience.
** Clarence: "Well, thanks for the help. I'm having an existential nightmare, and you can't even say a word!"
* HeWhoFightsMonsters: One of the interpretations of the ending in ''Black Plague''.
* HisNameIs: Eloff Carpenter records his final words on a cassette tape and says he knows the primary weaknesses of the Tuurngait, but before he can spit it out he's apparently dragged off and killed. "The species' primary weakness is--uugggh!"
* HiveMind: [[spoiler:The Tuurngait.]]
* HowWeGotHere: The intro cutscene of each installment.
* HopeSpot: on the ''Surface Station'' level of ''Requiem'', there's a helipad that Philip thinks is his ticket to escape. But when he gets the satellite dish running, the transmission he can send only calls in an air supply drop of items that can get him to the next level.
* HumansAreBastards: [[spoiler:That's what the Tuurngait thinks, anyways. If you [[OnlyTheWorthyMayPass pass its moral tests]], it declares you an example of MySpeciesDothProtestTooMuch - then you write in the email that it was wrong and give the coordinates to the mine, with the instructions "kill them all."]]
* HundredPercentCompletion: In ''Black Plague'', statistics at the end tell you how many artifacts and documents you collected. ''Requiem'' just has artifacts, but they actually serve a purpose - collect them all, and you unlock the GoldenEnding.
* ICannotSelfTerminate: [[spoiler:Red, because [[AndIMustScream he's too heavily controlled by]] TheVirus. Clarence because of a pretty logical reason: "How do you use a chainsaw when you don't have any hands?"]]
* ImprovisedWeapon: You don't DropTheHammer, you swing an actual hammer. Later on you find a small pickaxe (or ice-pick), but you're still pretty heavily outclassed. Then along comes the second game, which offers you no straightforward weapons at all. As in ''Overture'', you can still stun enemies by throwing objects at them, but other than that, you can only rely on your own feet and the patient use of stealth this time.
** WordOfGod stated that the weapons were removed because they were intended to be used for defense, but turned into a CherryTapping tool.
** One of the puzzles in ''Black Plague'' requires you to create a makeshift AerosolFlamethrower.
* IndividualityIsIllegal: Why the [[spoiler:Tuurngait]] rejects and destroys [[spoiler:Clarence once you manage to purge him from your mind]]. He's simply become too unique to reintegrate.
* IndyEscape: Once with an actual boulder, once with a rockworm.
* InterfaceScrew: The mere ''existence'' of [[spoiler: Clarence]] ''is this trope''.
* InvincibleMinorMinion: The Infected are generally this, but contrary to popular belief, enough physics object impacts '''can''' [[http://www.youtube.com/watch?v=pq-1UUe15tM actually kill one]].
* JerkassHasAPoint: [[spoiler:The Tuurngait states that selfishness in human would be catastrophic and that all humans pull in different directions. Well, the [[AntiVillain Tuurngait is no saint]], it does have a point. People were supposed to selfless and kill themselves or lock themselves up if they became infected. Many people didn't and turned into monsters that proceeded to kill or infect everyone else. The problem compounded itself until approximately 99.22% (100% minus the odds of survival given by the computer in Dr. Swanson's office) of the staff were dead.]]
* KillEmAll
* MacGyvering / MrFixit: A lot of the puzzles and threat-elimination are based on this. Some are a little more complicated, but it's [[JustifiedTrope pretty much justified]], since Philip is a professional physicist.
* MalevolentArchitecture: Why did that electrified cord have to land in that puddle of water? That's just one of the many questions you'll be asking.
** Why did those damn steam pipes had to be damaged, spraying dangerously hot steam everywhere ?
* MindScrew: ''Requiem'' in particular.
** Not to mention [[spoiler: Clarence from ''Black Plague'' - he ''can'' make you hallucinate, after all - not to mention his attempts to "make more space" in his new home.]]
--->[[spoiler:'''Clarence:''' Simply put... you see what I ''want'' you to see.]]
* MyGodWhatHaveIDone: Phillip [[spoiler:felt horrible when he unintentionally killed Dr. Swanson, courtesy of Clarence and his MindScrew.]]
* MysteriousAntarctica: Not set in Antarctica, but still a great VideoGame example of the "arctic wastes horror" genre. The whole series takes place in an unspecified location somewhere in the far north of Greenland. The atmosphere is captured brilliantly - from the very arrival aboard a chartered fishing boat to the discovery of [[spoiler:the secret base's well-hidden entrance.]]
* NiceJobBreakingItHero: See PlayerPunch.
-->[[spoiler:'''Clarence:''' Oh, one thing, before you get too overwhelmed with glee - I know murder can be a lot of fun, but... didn't you quite like that broad? [[KickThemWhileTheyAreDown Hey, I think that's a piece of her skull on your shoe.]] Wait, don't tell me you really thought... [[BlatantLies I thought you knew I was pulling your leg!]] Oh my, best laid plans, and all that... this, this is just ''[[SarcasmMode terrible]]''. Oh, you silly billy... Come on monkey... [[BlackComedy take a joke.]]]]
* NintendoHard: Combat in ''Overture''. You're fighting mutated versions of local fauna with a plain pickaxe, weak hammer, or even a nearly useless broom - what could you expect?
* NothingIsScarier / ParanoiaFuel: The Kennels in'' Black Plague''. You ''never'' see the monster, presumably[[spoiler: an insane, mutated version of Overseer Frisk, who has an aversion to light.]]
* NoticeThis: As in ''VideoGame/{{BioShock|1}}'', you can turn it off for greater immersion.
* OpenSaysMe: Most doors need a key, but there is one that opens by force. ''Requiem'', in the ''Residential'' stage has a fuse box that can be bashed open by throwing a rock (or a book) at it.
* OurZombiesAreDifferent: The Infected. And not only human ones.
* PowerfulPick: It takes a little practice to master, but the pickaxe (and the weaker hammer) can become a powerful and invaluable tool and melee weapon, once you get the hang of it.
* PsychologicalHorror: The core premise of the games, as highlighted in the NothingIsScarier entry. It's all very well executed, often with many [[SubvertedTrope subversions]] of classic horror tropes. It also makes very effective use of various {{Primal Fear}}s.
* PuzzleBoss: [[spoiler:Amabel. You need to turn a wheel to raise a crate, then drop it on her head. The real problem isn't figuring out what to do, but doing it while she keeps rushing you.]]
** The rockworms, [[spoiler: Dr. Eminiss and Clarence (in his materialised form) are other obvious examples.]]
* RagdollPhysics: Mostly averted, but not completely.
* {{Sandworm}}: Or more precisely, a "giant gray rockworm". The real InvincibleMinorMinion, and it can also kill you in one hit. Fortunately, there are only two or three of them.
* SavePoint: Voluntary savepoints are done in an interesting fasion: They're ancient cylindrical lantern-like artifacts [[spoiler: apparently brought to Earth by the Tuurngait and later rediscovered when the mine and underground base were built in the 20th century. Unfortunately, these strange objects help the Tuurngait see into your mind and secretly infest it.]]
* ScrewDestiny: One possible way to view the ending of ''Black Plague'' is that [[spoiler:Phillip refuses to be the Tuurngait's pawn]].
* ShoutOut / {{Homage}}: Lots. For instance, Howard's and Philip's names hint at Creator/HPLovecraft himself, and the Archaic's library contains copies of ''The Necronomicon'' and ''De Vermiis Mysteries''.
** Several food cans are labelled Uncle Cthullhu's Squid Soup".
** The crowbar from Overture, needed for solving a puzzle, was previously owned by some long-dead arctic explorer [[VideoGame/HalfLife named Freeman]].
*** In ''Black Plague'' the Infected have a blood goatee, BlackEyesOfEvil (which resemble glasses from far away), and some wield crowbars.
** The storytelling is heavily inspired by Poe and Lovecraft. Also, the plot and atmosphere is very similar to Creator/JohnWCampbell's short story ''Literature/WhoGoesThere'', famously adapted to film by Creator/JohnCarpenter as ''Film/TheThing1982''.
** [[spoiler:Clarence (Phillips's DarkSide) has a voice strikingly similar to his namesake from the classic holiday movie ''ItsAWonderfulLife''. He even references the movie in a cheerful fashion when he chooses himself a name [[MoodDissonance while fully infecting and mentally torturing Philip]].]]
** The ''VideoGame/DonkeyKong'' like area in Requiem, where flaming barrels roll down several vertically adjacent slopes while music that sounds suspiciously familiar.
* SilentProtagonist: Philip is an interesting subversion, since he narrates the intro cutscenes and you can read his thoughts and ideas about an object or situation in-game after clicking the right mouse button.
* SpringLoadedCorpse: The second game's final enemy.
* StealthBasedGame: You ''can'' try to fight anything you come across, but considering that you only have a pickaxe, do you ''want'' to ? Not to mention that you're utterly weaponless in the two sequels (if you don't count object-throwing).
** Philip even shows his GenreSavvy side and lampshades the need for stealth in one of the earliest levels of ''Overture'' (where things start looking really serious).
* SubsystemDamage: The most basic sort: when you're injured, you limp.
* SurrealHorror: The events in the games get gradually more and more bizarre, especially in ''Black Plague'' and ''Requiem''.
* TakingYouWithMe: [[spoiler:Clarence word-for-word when he gives up begging for his life. [[InterfaceScrew And remember how he can cause hallucinations]]?]]
* TemptingFate: Traveling on your own and ''completely alone'' to the most isolated regions of Greenland in search for answers about your father's mysterious past requires either utter GenreBlindness or "I've got nothing to lose" sentiments.
* TenSecondFlashlight: In the first two games. ''Requiem'' uses an InfiniteFlashlight (if you're hallucinating it all, no need to hallucinate battery charge drain). Averted though with the glowstick, which Philip begins the game with. It casts a shorter and dimmer (though more peripheral) range of light than the flashlight, and never runs out.
* TheDevTeamThinksofEverything: If you try to hop the fence in ''Requiem'' on the surface, you magically teleport back to the center of the level.
* TheOtherDarrin: Philip has a vastly different voice actor in the English version of ''Overture'' and ''Black Plague''. All the more strange, since the rest of the voice cast remains the same throughout the series.
** ''Overture'' had a tiny, yet effective voice cast of two people. The ''Overture'' incarnation of Philip (though uncredited) was voiced by Tom Jubert, the script writer of the series (since Frictional had little budget to create ''Overture'' and could afford a larger voice cast only after the game achieved success). Many fans consider Overture's Philip to be the canon version, since he at least sounds like an Englishman in his 20s or 30s, unlike the suddenly North American-accented 40s-sounding Philip from Black Plague.
* TronLines: Twice in ''Requiem'', a heavy metal ball engraved with exactly this trope - complete with the signature "T" on one side - has to be rolled around and used as a power source for a couple of puzzles.
* {{Unobtainium}}: The Archaic has discovered seventy different kinds.
* VideoGameCrueltyPunishment: [[spoiler:In ''Black Plague'' you can set a Tuurngait on fire at one point. Then it turns out there's a door right behind it that only a zombie would be strong enough to tear down.]]
** Especially bad if you [[spoiler:pulled the lever to find out WhatDoesThisButtonDo, as the Infected will walk right into it. Then the puzzle can't be solved without taking the same approach to a different lever.]]
* TheVirus: [[spoiler:Called such in-game, it's how the Tuurngait [[YouWillBeAssimilated replenishes itself]]. Interestingly, it apparently began as a mutually beneficial MentalFusion, or so the HiveMind claims.]]
* VoiceWithAnInternetConnection: Subverted in ''Overture'' - Red can only contact you via walkie talkie, has no idea where you are or whether you're still alive, but he's so lonely he keeps talking. Played straight with Amabel Swanson in ''Black Plague'', and sort of bent in ''Requiem'' as Red, Dr. Eminiss, and the bland voice on the intercom all counsel and taunt you.
* ViolationOfCommonSense: Well, it fits the theme, but one puzzle requires you to [[spoiler:set yourself on fire so a trap will malfunction and someone else can get through it safely]]. Incidentally, [[StupidityIsTheOnlyOption stupidity is not the only option]]--it's just the only moral one (as well as the only one that allows you to go on with the game).
** Not to mention another puzzle where you have to inject yourself with an unknown chemical in order to put yourself in a chemically-induced coma so that the door you need to go through will be unlocked. The function of the item is actually explained in a nearby note, but it is entirely possible to miss it and arrive at this result anyway through good old experimentation.
* WhenAllYouHaveIsAHammer

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