[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/2277255-knock_knock350_3126.png]]
[[caption-width-right:350:Ready or not, here I come.]]
A horror game created by [[Creator/IcePickLodge Ice-Pick Lodge]], the same folks behind ''VideoGame/{{Pathologic}}'', ''VideoGame/{{Turgor}}'', and ''[[VideoGame/CargoTheQuestForGravity Cargo! The Quest for Gravity]]''. The game was successfully funded through Kickstarter, and can now be purchased on Steam.

In ''Knock-knock'', you play as The Lodger, a disturbed young loner, as he's caught in a nightmarish loop of suddenly waking up in an unfamiliar house again and again, without the security of knowing what's real and what's just a part of his dream. But with those visitors after him, who cares? Whether it's all real or not, the only reassurance he'll get comes with the dawn.

The basic gameplay is simple, but the game doesn't hold your hand through even the basic mechanics. You wander through a randomized house avoiding horrific monsters, as you run the clock out until dawn. Hiding rewinds the clock, and you can only hide behind furniture, so sometimes it's better to outright run.
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!!This game provides examples of:
* TwoAndAHalfD: The rooms are 3D with interacting shadows and objects, but you can only move in two dimensions when not moving between levels.
* AnimeHair: Just look at that 'do!
** Somehow [[JustifiedTrope justified]] - Every level starts with the Lodger getting up in the middle of the night ([[MindScrew probably]]), so it's an extreme case of bed-hair.
* AnotherDimension: The real world and the dream world. Unlike other examples, it is impossible to tell which one, if either, [[MindScrew is real]]. Weird stuff happens in both.
* ArcWords: ''"You thought about it."''
* AttackOfThe50FootWhatever: [[spoiler:Reaching the monster symbol on the 'map' brings a giant entity that looms over your house for the remaining length of the game. Whether this is the monster shown in the trailers or the local [[StringyHairedGhostGirl ghost girl]] is determined by your willingness to do some side-tasks and has an impact on the ending.]]
* BigBad: [[spoiler:The Bogeyman. Sort of.]]
* BigGood: [[spoiler:The [[StringyHairedGhostGirl ghost girl]]. [[MindScrew Maybe]].]]
* {{Bizarrchitecture}}: The house becomes this in later stages, as it grows in size but retains the same random generator. So you'll see basements going five stories deep or towers that connect to each other in bizarre ways.
* BodyHorror: Most of the ghosts you encounter, [[http://img.gawkerassets.com/img/17u5ct3cw742xjpg/ku-xlarge.jpg some more than others]].
* BreakingTheFourthWall: Whenever the Lodger speaks, he turns his head to the camera. It's never really stated whether he's talking to himself or actually talking to the player. There are instances, however, when he seems to plead for help from ''someone''.
* CreepyShadowedUnderEyes: Doubling as ExhaustedEyeBags for The Lodger.
* DarkAndTroubledPast: The Lodger and his family have one. Each of the Lodger's ancestors added a room to their ancestral home, but the Lodger claims not all legacy is good and rarely goes into some of said rooms. As for the Lodger himself, it's unclear. [[spoiler: The diary entries that can be found later in the game claim the author's son and two unrelated children lived in the house and were being hidden from the government. They were eventually found out and taken away, and then soon afterwards, a little girl(?) appeared in the house. Her body was seemingly invisible, she didn't appear to need to eat, and she was wearing white clothing. The diary author wondered if she was a product of government-run experiments. One day she brought the diary author brown leaves and he had as much of an idea as to what that [[MindScrew meant as the audience does]]. It's hard to be sure whether the diary author is the Lodger himself and the children were his to take care of, or if he is the mentioned son. Either way it suggests a less than happy history attached to both the Lodger and the house itself.]]
* DoubleDoubleTitle: ''Knock-knock''.
* EeriePaleSkinnedBrunette: The Lodger, again.
** Also applies to the local StringyHairedGhostGirl.
* EvilLaugh: Happens every time you walk into a ghost.
* GaiasLament: The Lodger at one point comments on how the forest is dying out- how he's been unable to find any new plants growing, the soil is soggy and barren, and the only fauna left are the insects.
* GainaxEnding: Both endings are 30-second clips that will only make things even more confusing if you haven't riddled out the game's symbolism and found (and memorized) all the diary entries. [[spoiler:They revolve around the house as a representation of the Lodger's mind, and the monsters, the Bogeyman in particular, as his repressed memories of what happened to the orphan girl during the mass abductions.]]
** Pagurian: [[spoiler:Obtained if the Lodger avoids seeking out diary pages and Fragments of Reality in favor of staying safe and avoiding hostiles. As the Bogeyman draws closer, the Lodger decides to shut himself inside his house.]]
** Break the Cycle: [[spoiler:Obtained after the Lodger collects Fragments of Reality, looks for diary pages, and seeks out the weeping child Guest who appears in the later stages. The Bogeyman turns into the girl, and the Lodger moves out, leaving his house and the forest behind. In the especially good ending, the forest will get restored as well.]]
* GoMadFromTheIsolation: What happened to the Lodger, probably. Even with all the MindScrew going on, it's hard to find his monologues sane.
* HearingVoices: The Lodger is plagued by some invisible speaker. A young girl or a raspy man tells him things. Most of it just encourages paranoia.
* IceCreamKoan: Sometimes the Lodger is profound and concise. Other times his words are indecipherable to anyone besides himself.
* TheInsomniac: The Lodger has ExhaustedEyeBags as a result.
* LiteralMinded: The Lodger's father liked to speak in metaphors. The Lodger said he was the last member of the family to do so. As a child, his father gave him a diary and told him to write in it. When the diary is full, the Lodger's life would be over. The Lodger took him literally and decided to infrequently write in the diary and write as small and concise as possible.
* MadScientist: Subverted. He is mad and he is a "world-ologist", but his madness is (mostly) unrelated to his work. As a scientist, his job is to watch the forest, take observations, and record the conditions (air, soil, water, etc.) of the forest just like his ancestors. The forest has been in decline for years and the animals have fled. Since he is isolated to better conduct his studies and experiments, he has been slowly losing his mind.
* MaybeMagicMaybeMundane: The Girl. While the Lodger created the "Guests", the girl could be a product of [[spoiler:the government's experiments]] or she could be another construct of his mind. Either way, it's hinted at that she is the girl from his diary.
* MindScrew: Good luck trying to figure out what's going on. The only clues you get are [[UnreliableNarrator The Lodger's monologues]] and some diary pages, and even ''those'' rarely give you any information whatsoever, unless you look for specific ones. Unlike many games, though, this also can be said for the game-play. Was the girl another construct of his mind or a product of [[spoiler:government experimentation? Was there government-sanctioned child kidnappings or was it in his head? [[UnreliableNarrator Did the Lodger actually have a son, was ''he'' the son, or was it all just another fiction?]]]] Is he actually a "world-ologist" who is paid to watch the forest or is he just a madman in the woods? To quote WebVideo/{{Markiplier}}, the game is a bunch of loose threads that don't connect or are fully explained. Several ideas are thrown out there and many of them contradict others.
* MissingMom: According to the diary entries, [[spoiler:a father once lived in the Lodger's house with his son, but his wife is never mentioned. His child, along with two other children, was taken by the government before the story's start.]]
* NonStandardGameOver: It's virtually impossible to get a game over in the levels that require you to avoid ghosts, as they simply restart the level. Later in the game, however, wandering the forest without care can get you a game over screen with the Lodger apparently having [[GoMadFromTheRevelation gone mad]].
* PajamaCladHero: The Lodger is always "waking up". He is never shown doing his work during the day. He wakes up in the real world and waits for dawn. After he checks the house and woods, the game makes a JumpCut to him waking up in his "dream" world.
* PerpetualFrowner: You see the expression on the Lodger up there in the page image? He wears it for 90% of the game.
* SanityMeter: One appears after the arrival of the Bogeyman. It drains slowly whenever the Lodger isn't in his home, and it's persistent for the rest of the game -- if it runs out before the very end, the Lodger loses his mind the next time he tries to go outside, forcing the player to start the game over.
* SanitySlippage: The Lodger is a bit off-kilter at the best of times, but after the Bogeyman appears, his brief voice clips become more and more deranged. [[spoiler:You get a NonStandardGameOver if he slips all the way, since he's too exhausted and terrified to leave his own house.]]
* SickeningCrunch: The player never actually hears it, but the Lodger can state at one point that he "feels like (he) stepped on something living."
* {{Sleepwalking}}: The Lodger blames the first few oddities on this.
* [[SpeakingSimlish Speaking Gibberish]]: The Lodger's speech is always a series of garbled high-pitched mumbles. [[spoiler:Other characters speak normally, however. This includes the Dopplegangers that appear from time to time- who seem to have the same voice actor but speak coherently.]]
* StringyHairedGhostGirl: The Lodger can encounter her while wandering around the woods. Walking into her allows you 'catch a glimpse of the other world'. [[spoiler:She can also appear over your house to indicate which ending you'll probably get.]]
* TrailersAlwaysSpoil: The game trailers pretty much give away most of the designs for enemies - something vital in most horror games. [[AvertedTrope Averted]] when it comes to any sort of plot though.
* TroublingUnchildlikeBehavior: It is hinted at that the Lodger has been playing his "games" since childhood. His games often involved bringing on hauntings or, as in one game and if a certain condition is met, the death of the player (he is the only player). He never died (in-game or real life) because the condition is outlandish (like someone opening the front door when he is completely isolated from society), but his growing madness is starting to fulfill that condition...
* UnreliableNarrator: The Lodger, oh so much. Most of his monologues seem completely detached from reality ([[MindScrew or what passes for it, anyways]]) and sometimes even contradict each other.
* VagueAge: The Lodger's age is never stated. Physically, he looks like a kid, but verbally, he sounds like an adult. [[spoiler:If the diary entries are his, they suggest the latter.]]
* TheWallsHaveEyes: Some rooms have eyes scribbled on the walls or ceiling. Also used to symbolize a 'breach'. [[spoiler: Some rooms can also have massive holes in the wall with giant eyes behind them.]]
* YourMindMakesItReal: Many of the game's supernatural events seem to arise from the Lodger's own confused state of mind. This is what makes the game a MindScrew.
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