[[quoteright:320:http://static.tvtropes.org/pmwiki/pub/images/flownexus_7925.jpg]]
[[caption-width-right:320:Think [[HubLevel the nexus]] looks a bit unsettling? Just wait.]]

''.flow'' is a [[FreewareGames freeware]] ''YumeNikki'' [[SpiritualSuccessor fangame]] created in the RPG Maker 2003 engine by a Japanese developer going by the alias "lol". Like ''Yume Nikki'', exploration, surrealism, and atmosphere are the basic themes of the game; but unlike ''Yume Nikki'', this one has a ''lot'' more disturbing content and horror elements added in. ''.flow'', like ''Yume Nikki'', is an incomplete game, but as of 0.10 and onwards, the game now has a proper endgame and multiple endings, though the "multiple" status is of some debate.

''.flow'' stars a young girl known only as "[[MeaningfulName Sabitsuki]]", who uses her computer -- in one way or another, as the method is not explicitly mentioned -- to explore a surreal world while collecting special abilities known as "effects". These effects change Sabitsuki's appearance, varying from a witch outfit and a broom to a corpse. Some effects, such as the whistle and the iron pipe, can affect [=NPCs=] and certain objects; although most effects only have a small animation or side-effect that can be activated, while some are simply cosmetic.

Much like [[YumeNikki the original]], there are no provided explanations to what is seen or discovered in the game, and the game is practically textless outside of menus. Fans [[EpilepticTrees are left to speculate]] and come up with their own interpretations; most [=NPCs=], events, and areas are all [[FanNickname nicknamed by fans]], be it from a filename or elsewhere.

The latest version, v0.192, can be found at lol's site [[http://rustlimbo.webcrow.jp/games/flow/index.html here]], with an English translation available [[http://www.mediafire.com/download/t5za389klzn2d2t/flow_ver0.192eng.rar here]]. Various other versions, both the Japanese originals and any English translations, can be found on the fan wiki [[http://dotflow.wikidot.com/downloads here]]. The author, lol, has a [[http://rustlimbo.webcrow.jp/ personal site]], a [[http://www.pixiv.net/member_illust.php?id=269411 pixiv account]], a [[http://lolrust.deviantart.com/ deviantART account]], a [[http://twitter.com/lol_rust twitter page]], and a [[http://lol-rust.tumblr.com/ tumblr account]].

[[IThoughtItMeant Not to be confused]] with the 2006 freeware life simulation game ''[[http://en.wikipedia.org/wiki/Flow_%28video_game%29 Flow]]''.

'''Note:''' Unless otherwise stated, assume all examples below apply to the latest version of the game.

Beware of many '''unmarked spoilers'''!

----
!!''.flow'' provides examples of:

* AbsurdlySpaciousSewer: The sewers area, while only spanning a few rooms, is rather large. It houses the bar/restaurant named "the Sugar Hole", which is home to the Cleaners.
* AcidTripDimension: The world accessed by Sabitsuki's computer. Fans are divided on what to name it, but it's usually referred to as Sabitsuki's mind/[[DreamWorld mental world]] or simply .flow.
* {{Adorkable}}: There's something rather cute about seeing Oreko frantically working on her machine in her house, occasionally sleeping on her arms over it (implying she'd fallen asleep in the middle of working), or simply sitting on the stool and swinging her legs. As well as the fact that whenever Sabitsuki fires the handgun, Oreko instantly goes to check on her computer.
* AllJustADream
** The mental world, at first, seems to just another form of a dream world... that is, until you uncover certain events that can affect the real world.
** The Nightmare event seems to be simply a dream, though one could call that questionable given that Sabitsuki has to pinch her cheek to get it, which usually denotes waking up.
** The [[spoiler:third ending]] involves Sabitsuki (or is it Rust?) waking up from her bed, calling the reality of [[spoiler:the entirety of the game beforehand]] into question.
* AllThereInTheManual: The gas-mask maids are named "Cleaners" in a drawing lol posted on his pixiv account.
* AmbidextrousSprite: Averted; Sabitsuki always holds objects in her left hand no matter which way she is facing, and the Tattoo effect's shoulder tattoo always appears on her left arm. Smile also always holds his hammer in his left hand; the Sabitsuki Kaibutsu also always hold their pipes in their left hands.
* AnArmAndALeg
** The Tumbling Doll effect removes all four of Sabitsuki's limbs, forcing her to move or crawl at a slower speed than usual. Said effect is found by interacting with, appropriately enough, a chainsaw.
** The third ending has [[spoiler:a Cleaner chainsaw off Sabitsuki's legs. Sabitsuki's fate after this is ambiguous.]]
* {{Animorphism}}: The Cat effect gives Sabitsuki white cat ears and a tail, and its side-effect is turning Sabitsuki into a small white cat. This side-effect allows Sabitsuki to pass through small gaps.
* AntiHero: Possibly Rust, who is controlled throughout the endgame. Notably, her sprite is paler and more detailed than Sabitsuki's sprites, giving her a sickly look, but only when in the mental world.
* AprilFools: ''.flow'' had an April Fools update in version 0.16, otherwise known as the "April Fools" version. Only one area of events is accessible in the mental world, exclusive to this version, and only serves in adding more questions. Of course, due to its status as ''.flow''[='=]s April Fools joke, its canon status is definitely debatable.
* ArtificialLimbs
** The Machine effect gives these to Sabitsuki, as well as some kind of headgear.
** The Television effect gives Sabitsuki a television for a head. Its side-effect is Sabitsuki switching on the TV screen, which can show a number of things, such as bloodstains or Sabitsuki's face.
* ArcNumber: 97920 appears both on the walls of some buildings and in the FC glitch event.
* ArtShift: The [[NintendoEntertainmentSystem Famicom]] or FC world is rendered in an 8-bit style, complete with 8-bit sounds and music.
* BellyMouth: All red demons have a huge mouth on their stomachs.
* BerserkButton: None of the Kaibutsu appreciate getting smacked in the face with the pipe. The bar Kaibutsu counter-attacking upon getting smacked has been interpreted as one.
* BlackScreenOfDeath
** Used in both Corrupted School events, right before either [[spoiler:a Kaibutsu or red demon kills Sabitsuki/Rust]], [[spoiler:Smile kills Sabitsuki]], or [[spoiler:a very Kaibutsu-like Rust kills Smile]]. [[NightmareFuel Unsettling laughter can be heard all three times]].
** All three endings make use of this:
*** In the first ending, the scene cuts from Sabitsuki standing on a balcony to a black screen.
*** In the second ending, the scene cuts from Sabitsuki/Rust and [[spoiler:a Cleaner from the Sugar Hole]] standing on the balcony to a black screen.
*** In the third and final ending, the scene cuts from [[spoiler:Cleaner pulling out a chainsaw, and then Sabitsuki/Rust charging at her]], to a black screen.
* TheBlank: A special maid in Sweet Sugar who seems to only have hidden eyes upon first glance, upon interacting with her after eaten five meals at the Sugar Hole, is revealed to have a giant hole in her face.
* BlobMonster
** The Slime effect turns Sabitsuki into one of these, with the action button causing her to sink into herself.
** In the apartments, two orange blob-monsters can be found. They make bubbly sounds when interacted with, but otherwise do nothing.
* BloodFromTheMouth
** Several events will add to Sabitsuki's "Erosion Counter"[[note]]alternatively called the "Corruption Meter"[[/note]], and as the counter goes up, more and more blood appears in her room, eventually accompanied by [[spoiler:what may be life-support devices near the computer]]. One of these events in particular has Sabitsuki coughing blood from the mouth before fainting.
** The best way to distinguish an enraged Kaibutsu from a calm one: calm Kaibutsu resemble normal schoolchildren with slightly bloody faces, while enraged ones have very bloody faces, usually accompanied by some kind of body horror.
** Blood can be seen on Smile's mouth, as well as several mouth posters in the school area.
** One area of the body has a very detailed mouth in the background, decayed and bleeding profusely.
* BloodierAndGorier
** Oh yes. This game redefines "rusting" to mean "grows increasingly bloodier", and does not let you forget this at any point. Several events and areas of the game rust, be it over the course of the game or due to triggering an event/effect, and notably the whole mental world goes into a darker and more bloodier state during the endgame. [[spoiler:Sabitsuki herself]] also ends up slowly rusting over the course of the game.
** The most disturbing scene in the game, known as the "Dying Girls event", has Sabitsuki witnessing nine black-haired girls spontaneously exploding one after another, and then witnessing viscera splitting out of the stomach of a large black-haired girl on the wall. After interacting with the corpse of the large black-haired girl, Sabitsuki's vision goes blurry and she wakes up.
** The endgame has far more blood and gore than the rest of the game does -- you only need to look as far as what the red demons do to Rust.
* BodyMotifs: Pops up frequently, usually in a diseased or otherwise deformed way. There is a subtle yet present focus on Sabitsuki's legs (or lack of them) in particular.
* BodyHorror: All over the place. There are very many examples of body horror to be found.
** A few of Sabitsuki's effects invoke this: the Arm effect that makes her look like Monoko's five-armed form; the Viscera effect has her walk around with her [[{{Squick}} intestines just hanging out]], and its side-effect is Sabitsuki attempting to stuff them back in.
** In the endgame, as you get hit by more and more red demons, Rust decays more and more, causing her to become blood-covered and severely mangled, until it gets too much for her and causes her ''head to explode''.
* BroughtDownToNormal: Rust has no access to any of Sabitsuki's effects, though she does bring out the iron pipe during certain events. Despite this, she can enter some places Sabitsuki could not.
* CarryABigStick
** Sabitsuki uses an iron pipe to kill things. Rust also uses one in certain events despite having no access to any effects.
** The bar Kaibutsu wields a crowbar, and Sabitsuki's lookalike Kaibutsu also wield pipes.
* {{Catgirl}}: The Cat effect, as described above under {{Animorphism}}.
* ChainsawGood: The Cleaners are associated with chainsaws, though their "good" status is debatable.
* ChekhovsGunman: Thought those [[spoiler:Cleaners]] were simply another resident in the mental world? Think again.
* CheshireCatGrin: Unnerving smiles can be found in many places, usually bleeding. Smile, true to his name, has one very unnerving one, and the twintail Kaibutsu's enraged form has a very bloody one. Occasionally, Sabitsuki or Rust can spout one at times.
* ColorMotif: Both dark red and orange come up in the game frequently. The dark red is most likely a reference to rust and/or blood, while the orange is one for Oreko and possibly Sabitsuki herself.
* CoolMask
** The Gas Mask effect. A variant found in the Debug Room gives Sabitsuki one with twintails.
** The Cleaners all wear gas masks, and are never seen without them.
* CosmeticAward
** Obtaining the special Flower, Orange, Rust, and Smile menus simply change the look of your menu.
** [[AvertedTrope Averted]] with the Sugar menu: when equipped, it increases the likelihood of getting the meal instead of just the drink at the Sugar Hole.
* CriticalExistenceFailure: The endgame has a glitch that involves taking damage in the FC world. When you leave, Rust will appear to not have taken any damage, but actually has.
* {{Cyborg}}: Sabitsuki with the Machine effect.
* {{Cyclops}}: The Monoeye ability gives Sabitsuki a single, large red eye on her face. Its side-effect is blinking in rapid succession, and can also make an eye graffiti in the apartments blink.
* DarkerAndEdgier: The general atmosphere of ''.flow'' is much darker than ''Yume Nikki''.
* DarkWorld: The Corrupted School and Parade Ward of the asylum are even scarier versions of the school and asylum, right down to the [[HellIsThatNoise incredibly unsettling laughter]] in both.
* DebugRoom: Accessible though modifying the game in RPG Maker. It contains all the effects, a speed-up skill, and teleports to certain events such as the Nightmare or Flying event. Interestingly, some of the effects (such as the Gas Mask effect) have comments left by lol on them.
* DoesNotLikeShoes: Oreko doesn't wear shoes in any of the locations you find her in.
* DownerEnding: No matter which ending you choose, Sabitsuki does not meet a very good end. However, given the events of the third ending, some have come to interpret it as a BittersweetEnding.
* DreamLand: The mental world, though there are hints that it's not quite a "dream".
* DreamPeople: Every [=NPC=] in the world via the computer. That is, [[spoiler:until the second and third endings reveal that the Cleaners also exist in the real world]]...
* DreamWithinADream
** One theory regarding the endgame and the endings, since Sabitsuki has to use the computer in the mental world to discard her effects. The theories sometimes use the fact that Rust uses a different exit animation (red screen static instead of pinching her cheeks) as supporting evidence.
** The Nightmare event seems to be one of these; though you get it by manually exiting .flow, it takes place just before logging off.
** The Corrupted School events are occasionally interpreted as these; the Sabitsuki version as a nightmare, and the Rust version as a revenge fantasy of sorts.
* DrivenToSuicide
** One interpretation of [[spoiler:the first ending]]. The [[spoiler:second ending]] could also be interpreted as one, depending on how you look at it.
** One theory states that Smile did this at one point, seeing as you find him on a balcony in one of his many appearances, and balconies commonly have a negative connotation in ''Yume Nikki'' games.
* DropTheHammer: Smile carries a hammer with him in most places you find him. Notably, he brings out the hammer after you attack him in his house or pull out the pipe in a certain room of the school, and attacks Sabitsuki with it in her Corrupted School event.
* DummiedOut
** The debug room, only accessible by modifying the game through RPG Maker.
** One of the rooms in the apartments, by the door leading to the snow area, used to be accessible and had an [=NPC=] resembling a brunette girl wearing a straw hat living inside. This room is only accessible in very early versions of .flow and does not exist in future versions. Interestingly, the [=NPC=] resembles the girl who hides within some plants in the Plant Labyrinth.
* EmptyRoomPsych
** Several rooms are empty and serve no purpose. In the endgame, however, some of these empty rooms now house red demons.
** A certain room in the apartments seems empty at first, but walking around it has a chance of causing an orange blob-monster to fall from the ceiling.
* ExactlyWhatItSaysOnTheTin
** Kaibutsu, which means "monster", is a perfect name to describe the {{demonic spiders}} the game throws at you.
** As with the red demons, who are certainly both red in appearance and demonic in both appearance and behavior.
* EyesAlwaysShut: Sabitsuki's sprite implies she has these, outside of the Monoeye effect and activated Cat effect, which give her open eyes. Art done by lol depicts Sabitsuki with open eyes.
* EyeScream
** Many posters in the school depict eyes which appear to be either bleeding profusely or heavily tattooed. Smile has + eyes, similar to these posters, which has caused speculation that they are either damaged, missing, or heavily tattooed. It's worth noting that the effect you get from a version of Smile is the Tattoo effect, giving credence to the tattoo theory.
** The apartments area has a wall graffiti of an eye. Sabitsuki can smack it with her pipe and cause it to bleed.
* TheFaceless
** The faces of the black-haired girls are never seen; even in the Dying Girls event, where a larger one's face is barely seen, it's blank and almost immediately dissolves into blood anyway.
** The Cleaners' true faces are never seen, since they are always seen with their gas masks on.
** The Sweet Sugar maids, due to their incredibly small sprites, have no visible facial features, though one maid has a shadow over her face; see also TheBlank above.
* FiringInTheAirALot: The Handgun effect, which has certain effects on certain [=NPCs=], namely causing some to flee from Sabitsuki. If one fires in the air enough times in a row, Sabitsuki will run out of ammunition and have to reload the gun.
* {{Foreshadowing}}: The events of the endings are very subtly hidden all over the place.
** Notice how several effects do things to Sabitsuki's legs, such as replacing them (Machine, Plant, Slime) or removing them (Tumbling Doll, Ghost), and that the one speed-up effect, the Broom, is also the one that takes Sabitsuki's legs out of the picture, all implying that Sabitsuki has weak or bad legs? [[AnArmAndALeg Come the third ending...]]
* FlyingBroomstick: The Broom effect, which both serves the same function of speeding up the player as the bike in ''YumeNikki''. It is also similar to the Witch effect from the same game, down to being able to access a special flying event hidden somewhere in a maze or maze-like area.
* GainaxEnding: The game has three endings, each one less coherent than the last. It's even ambiguous to whether they're all the same or different courses of events.
* GameBreakingBug
** v0.19 initially came with one, a corrupted music file that rendered the city coast and monochrome beach inaccessible, causing one's game to crash and spam errors when accessed.
** Parodied in the FC world's glitch event, which roughly follows the same vein as ''Yume Nikki''[='=]s.
** Using the Plant effect during rain causes Sabitsuki to be overgrown to the point where she can't move, stripping you of all controls and making you unable to access the menu to escape. The only way to get out of this is to exit the game.
* GasMaskMooks: The Cleaners, who all wear gas masks.
* GirlWithPsychoWeapon
** Sabitsuki's killing implement of choice is an iron pipe. Her Kaibutsu-lookalikes also wield pipes.
** The Cleaners are associated with and seen wielding chainsaws.
** lol often draws Sister wielding a knife in their art.
* GoodGuyBar: The Sugar Hole, populated by Cleaners, one regular, and occasionally a special Kaibutsu known as the "bar Kaibutsu". Sabitsuki can get a drink or meal at the bar for varying prices.
* {{Gorn}}: A good deal of it, as standard for ''Yume Nikki'' fangames.
** For effects, we have the Tumbling Doll[[note]]Sabitsuki loses all her limbs[[/note]], Corpse, and Viscera[[note]]Sabitsuki's intestines hang out[[/note]] effects.
** Getting hit by red demons further and further decays Rust, to the point where her face is mangled and she's coated in her own blood.
* GottaCatchEmAll: All 24 effects as Sabitsuki, then the three "empty boxes" as Rust. All of the collectibles, especially the empty boxes, correspond to some part of Sabitsuki's mind.
* GuideDangIt
** You ''will'', at some point or another, need to look up some videos or guides if you want to find some of the effects. Let's not count out the empty boxes either, which can be even more troublesome than the effects to find, especially since Rust can't use any effects to aid finding them.
** Getting all the menu types are fairly straightforward, except for the damned Rust menu. To get the Rust menu, you need to raise the Erosion Counter to 100 points/two blood splatters (which becomes annoying if you've been doing things to decrease the Erosion Counter beforehand), go all the way to the Parade ward, and interact with the diseased-looking child Sabitsuki in her room.
** Getting the Nightmare event. You have to raise the Erosion Counter to ''250'' points. The blood splatters in Sabitsuki's room that one can use as a tally stop appearing after 200 points, so after that, it's basically guesswork until you get the event. Furthermore, you have to manually pinch your cheek to get it -- you won't get this event by, for example, getting killed by the bar Kaibutsu and waking up that way.
** Accessing the blocked-off room in the apartments requires you to have eaten at least 10 meals in the Sugar Hole and interacted with a Cleaner once during the current session. And even then, sometimes the traffic cone won't disappear, so you'll have to wake up and restart the session.
* TheHeroDies
** Sabitsuki can try to smack the bar Kaibutsu with the pipe, and get beaten to death and burnt in a furnace for her efforts.
** The "Bloody Room" event, where Sabitsuki coughs up blood and collapses.
** Similarly, in the endgame, getting hit by too many red demons causes Rust's head to explode.
** Sabitsuki doesn't get any better luck in the endings either, though due to the very ambiguous nature of the endings, whether she dies or not is unclear.
* HeroicAlbino
** Sabitsuki has white hair, and seems to have had it from birth, going by the younger versions of herself seen in the mental world, all of which also sport white hair. Rust also has white hair, though her "heroic" status is debatable and the subject of much speculation.
** Inverted with Smile, who has black hair, and also a debatable hero status.
* HiddenEyes: One maid in Sweet Sugar has a shadowed face. Sabitsuki also gets a shadowed face when exiting the maze found via the Streets' randomized event.
* {{Hikikomori}}: Sabitsuki appears to be one, [[IllGirl among]] [[MonstrousHumanoid other]] things.
* HollywoodCyborg
** The Machine effect, which replaces Sabitsuki's arms and legs with robotic parts and gives her some sort of robotic headgear.
** The girl in the Monochrome House seems to have robotic legs. A little girl in one of the asylum rooms, most likely a younger version of the same character, also seems to have robotic legs.
* {{Homage}}
** The more mechanical side of things seem to have been inspired by asgr's designs for cyborgs and machines. Oreko's computer and the machines in the deeper areas of the Industrial Maze are the most obvious examples.
** The Broom event is a direct homage to both ''YumeNikki''[='=]s Witch event and StudioGhibli's ''Kiki's Delivery Service''.
* TheHyena
** The Kaibutsu laugh a lot when enraged, hence the signature giggle associated with them, though most of their laughing has been reduced or outright taken out in later versions of the game (notably, the Candle World Kaibutsu keeps theirs).
** Smile laughs when attacked in his house or when attacking Sabitsuki in the Corrupted School event, leading to this interpretation; the Sabitsuki Kaibutsu in the same event also laugh a lot while chasing you.
* IllGirl: Sabitsuki is generally considered to be one (either physically, mentally, or both), due to the large amount of hospitals, diseased imagery, and similar motifs found in the mental world.
* ImageBoards: Has [[http://uboachan.net/flow/ its own section]] on Uboachan, and [[http://archive.uboachan.net/flow/ one]] in the archive. An extensive theory thread can be found on the archive [[http://archive.uboachan.net/flow/res/1097.xhtml here]], and at least two more can be found on the active site.
* ImaginaryFriend: It's speculated that Oreko is one to Sabitsuki.
* InvisibilityCloak: The Ghost effect's side-effect, which is used to confuse enraged Kaibutsu, making them easier to evade. However, it doesn't affect some other chaser-type [=NPC=]s.
* JourneyToTheCenterOfTheMind
** While most interpretations lie in speculation, it's generally agreed that the world Sabitsuki accesses via her computer is some representation of her mind.
** One interpretation of the path Rust takes to get the third ending.
* JumpScare
** The Kaibutsu Chase event, accessed via the Red Eye world, has one where one is chased down a corridor by three Kaibutsu, only to be struck down by a fourth one that comes out of ''nowhere''. The only way to evade it is by using the Ghost effect's invisibility cloak, where one can then either exit the event or head on towards the Corrupted School event.
** When you find Smile and his sister in their house, and decide to hit Smile with your iron pipe. Cue [[spoiler:Smile laughing hideously at you while his smile "radiates" in the foreground]].
** Attempting to attack the bar Kaibutsu leads to them counterattacking and killing Sabitsuki. Certainly a jump for the unprepared.
** One scene of the third ending requires you to hit the action button to continue. Cue [[spoiler:a very sudden blast of static, mixed in with creepy laughter]].
** A minor one in an empty room of the apartments: wandering around inside has a random chance to make one of those cute, orange blobs fall from the ceiling. It's quite shocking if one is not expecting it.
* KilledOffForReal
** The cyborg girl in the house on the Monochrome Beach, when piped, will never regenerate even if you end the session and start a new one. She won't disappear either, though, so you can keep beating her corpse if you're feeling particularly morbid -- though she makes a quiet, painful moan if you pipe her a second time, she makes no noises afterwards.
** To a lesser extent, the scarecrow and the girl hiding in the vines in the Plant Labyrinth: if either are piped, they will die and not respawn if one leaves and re-enters the room, but will regenerate in a new session. Oddly enough, piping either one will kill the other, implying the [=NPC=]s are both one in the same. Like the robot girl, you can keep beating them even after death, since they don't disappear like the usual [=NPC=]s.
* KillItWithFire: The aforementioned bar Kaibutsu will [[spoiler:stuff you into a furnace]] after killing you.
* LaughingMad: Creepy, unsettling laughter plays many, many times throughout the game. This laughter is normally associated with the crazy Kaibutsu, Smile, and deranged versions of Sabitsuki and/or Rust.
* LikeBrotherAndSister: It's speculated that Sabitsuki and Smile may have had a relationship like this in the past. It helps that the two have similar hair styles (though opposite hair colours), wield weapons, and [[ArsonMurderAndJaywalking have a tendency to smile creepily]], which also leads some to interpret them as actual siblings.
* LoveHotels: The Sweet Sugar hotel in the Psychedelic Town appears to be one of these.
* TheMaze: .flow has a few mazes, such as the White Maze and the Industrial Maze, although none of them are as hard or as confusing to navigate as some of ''Yume Nikki''[='=]s.
* MeaningfulName
** "Sabitsuki" translates to "covered in rust". Given the game's darker visual style and audio style, it really fits. The endgame has you play as Rust, implied she may be a "rusted" version of Sabitsuki. It's worth noting that Rust is very occasionally referred to as just Sabi, [[ExactlyWhatItSaysOnTheTin which literally means "rust"]].
** Smile, the nickname given to the black-haired boy seen around the school area, with plus-marked eyes and a tendency to give wide, creepy smiles. His little sister is very appropriately nicknamed Sister.
** The white-haired, humanoid creatures that may or may not chase you are called "Kaibutsu", meaning "monster".
** Oreko, whose name is a combination of part of the Japanese word for orange and the -ko suffix generally associated with girls.
* MentalWorld: Sabitsuki explores her mind in some fashion via her computer. It seems straightforward until you uncover the effects of the "Erosion Counter", where certain events can affect the real world. The endgame messes everything up even further, say nothing of the endings.
* MindControlDevice
** The Whistle effect causes most [=NPCs=] to move in the direction Sabitsuki is facing, and the Handgun effect causes most to move away from Sabitsuki or otherwise shock them.
** Using the Dress effect, making Sabitsuki curtsy, in the same room as any Cleaners will cause them to bow in your direction.
* MindScrew
** True to its [[YumeNikki predecessor]], ''.flow'' is filled with many MindScrew themes. ''.flow'' also takes the MindScrew themes further than ''YumeNikki'', an example of which can be seen above under MentalWorld.
** The endings are ''notorious'' for taking the whole real world vs. dream world perception and throwing it out the window.
* MiniGame: "Shinsoku Neko", a cute little 8-bit minigame where you control a black cat and try to catch as many fish as possible. It is harder than it sounds.
* MoneyForNothing: Averted: unlike ''YumeNikki'', money can be spent at the Sugar Hole to buy drinks or meals, and purchasing can unlock various things in-game.
** You have to buy the meal three times over separate sessions to obtain the Sugar menu.
** Several events, usually associated with the Sugar Hole or the Cleaners, are activated by eating the meal several times over separate sessions.
*** An event in the apartments is activated by eating ten meals and meeting a few other requirements.
*** An event in Sweet Sugar can be accessed after one eats five or more meals.
* MoneySpider: All [=NPCs=] have a random chance of dropping 100 coins when killed, and the money can then be spent at the Sugar Hole, either 100 for a drink or 300 for a meal of tea and cake. The non-Kaibutsu regular at the Sugar Hole can be piped for instant money every session, and lots of money can be farmed in the black-haired girls-filled room prior to the Dying Girls event.
* MoodWhiplash: Generally, travelling through the many areas of the game can lead to this, as one travels from areas with a dark or melancholy atmosphere to more colourful or brighter ones. A good example would be travelling to the Rainbow Maze, which is accessible through the Red Eye world full of deformed eyes and mouths.
* MonstrousHumanoid: All of the Kaibutsu fall under this. Sabitsuki seems to become one over the course of the game -- [[spoiler:specifically, she seems to become a Kaibutsu herself, as much speculation has pointed out]] -- and Rust is generally speculated to be one.
* MultipleEndings: Three of them, though their "multiple" status is the subject of much speculation: one after collecting all the effects, one after discarding all the effects, and one after collecting all three empty boxes and traversing the last area of the endgame. All of these happen by leaving your room by the nexus door in the real world.
* NightmareFace
** The Kaibutsu develop these when enraged. Depending on the Kaibutsu, they have a bloody face with a giant hole, a giant mouth, or two messed-up eyes. One special type of Kaibutsu, that resembles Sabitsuki, has a definite SlasherSmile.
** The Red Eye world, has strange things with wide-open mouths. In a random event, three of these things can appear in a group, one as a "door" leading to the Kaibutsu chase event.
** In the endgame, Rust's face gets messed up as she takes more damage via red demons. Even if there's not much to see due to the small sprites, your mind will fill in the gaps.
** The red demons themselves seem to have bloody, messed-up mouths for faces.
* NothingIsScarier
** There is a sequence involving an open, pitch black doorway with blood and gore splattered all around it, known as the "Bloody Room" event. You can't see what's on the other side of the doorway at first, and you never will as Sabitsuki. Sabitsuki refuses to go through the doorway, and the only way to leave the room is to step back. When you do, Sabitsuki starts oozing blood ''everywhere'', causing her to pass out and wake up to discover blood all over her keyboard. It's one of the few events that gives points to the Erosion Counter, causing blood to appear in Sabitsuki's room. In other words, whatever Sabitsuki saw on the other side of that doorway was so horrifying that ''it actually caused her physical harm''. The effect of this event is mitigated somewhat, however, when you enter as Rust and finally see what is behind the door; though since the entrance is accessed in a different place to where one goes with Sabitsuki, it's implied that both rooms may not be the same room.
** Getting the Corpse effect requires one to cross a large, black void from a cell. Certainly very unsettling, though it has arguably become slightly less after v0.15 added music to the area.
* PeopleJars: Two examples of this, both in the looping, orange-glowing industrial maze accessible by the sewers. One is a giant Oreko in a tube, where touching her changes the maze to a simple path. You can smash her tube, but all it does is keep the maze as a maze. Now, in the endgame, you can go deeper in via the simple path. While before the endgame you can't go any further, but as Rust you can go deeper in, and at the end of the path is a tube holding a giant Sabitsuki. This giant Sabitsuki in a tube is where one receives one of the three empty boxes.
* PlantPerson
** The Plant effect turns Sabisuki into one, and the side-effect causes the plants on her to grow. When used in rain, Sabitsuki overgrows to the point where she can't move. Fittingly, it's found in the Plant Labyrinth, after one causes the plants in the industrial snow area to overgrow.
** The Past Plant Labyrinth has many children overgrown with plants inside. A related area also has the nurse from the asylum slightly plantified.
* PosthumousCharacter: Some theories speculate that Oreko is a now-dead friend that Sabitsuki once knew, taking supporting evidence from the lamp area where her ghost is found.
* OnlyAFleshWound: The Tumbling Doll effect causes Sabitsuki's limbs to become cut off, and the Viscera effect has Sabitsuki casually walking around with her intestines hanging out. However, the endgame trumps both of those effects, as Rust continues to casually wander around even as her body is torn apart by the red demons.
* OneHitKill
** The Corrupted School event, where the [[spoiler:Sabitsuki-lookalike, pipe-carrying Kaibutsu kill you should they reach you]], and the same with [[spoiler:Smile if you interact with him]].
** In Rust's version of the Corrupted School, [[spoiler:the giant red demons kill her if she is touched]], and [[spoiler:she performs one on Smile when you interact with him]]. Due to a glitch in version 0.15, the [[spoiler:giant red demons]] did not actually kill Rust, though this glitch has been fixed in later versions.
** The Kaibutsu in the bar will kill you if you try to smack them with the pipe.
* OrcusOnHisThrone: There is a room in the body area where a black-haired girl sits on a throne of flesh. If you kill her, Sabitsuki can sit there as well.
* OrWasItADream: The Erosion Counter events and ''especially'' the endings leave one questioning whether or not. See also DreamWithinADream.
* PerpetualBeta: Although it's still farther in development than ''YumeNikki'', version-number wise, as ''YumeNikki'' never went past version 0.10.
* PettingZooPeople: Sabitsuki with the unactivated Cat effect equipped.
* PointOfNoReturn: Entering the endgame. Once one has discarded Sabitsuki's effects, there's no getting them back, rendering them forever unusable from that point on; several events also become permanently inaccessible, such as the Sugar Hole, and any event requiring effects to activate or reach them. There's no warning given (though some English translations do add one in) so without prior knowledge you could end up discarding all your effects before unlocking or seeing everything. However, if you haven't saved after entering the endgame, you can just close and re-open your save file.
* RandomEvent: Several found all over the place, as par the course for ''Yume Nikki'' fangames.
** All the events connected to the Erosion Counter (Bloody Room, Dying Girls, bar Kaibutsu) are randomized.
** The Streets area has a randomized event where one can either gain access to a previously-unaccessible part of the area, or see [[SarcasmMode pleasant sights]] such as a Kaibutsu beating up a hunk of meat or a maid standing menacingly with a chainsaw behind a line of cones.
* RandomlyDrops: Killing [=NPCs=] has a chance of dropping 100 yen every time. Several events, such as the Dying Girls event and the bar Kaibutsu, have a chance of randomly appearing every trip to the mental world.
* RavenHairIvorySkin: The black-haired girls have paper-white skin that contrasts with their hair. It has the effect of making them look somewhat sickly, which fits given the Dying Girls event and that one is seen in a hospital bed in the past Parade ward.
* RedEyesTakeWarning: Sabitsuki is often depicted by lol with red eyes, and both the Monoeye and Cat effects give her red eyes. Rust has dark red eyes on her sprite.
* RelationshipValues: There is a value for the relationship you have with Oreko, known as the Friendship Meter. Interacting with Oreko nets you five points, and interacting her with the Diving Helmet effect activated can net you an extra five, whilst killing her subtracts ten. Thirty points and up, a ghostly Oreko will appear in the lights-filled area where you obtain the Machine effect, and interacting with her teleports you to a place where you can get the Orange menu.
* RoseHairedGirl: Charlotte, the girl who sits by the fire in the alleys leading to the Dead Hole. She doesn't do anything but sit by the fire, and if you put it out using the Watering Can effect, she just relights it when the weather clears.
* SchmuckBait
** As in ''YumeNikki'', the inactive Kaibutsu don't like being attacked. ''Especially'' the bar Kaibutsu.
** Attempting to attack Smile just makes him [[NoSell laugh at you]].
* ShoutOut
** In particular, there are many that refer back to ''YumeNikki'':
*** The Arm effect makes Sabitsuki look like Monoko's five-armed form, and an image similar to Uboa also appears on the wall of a dead end in the temple maze accessed via the ocean world.
*** More obscurely, the Tumbling Doll effect is functionally similar to the Severed Head effect, and is found in an endlessly looping area full of Kaibutsu.
*** Everything about the Witch effect. An [=NPC=] resembling witch Madotsuki appears in the FC world, and interacting with her gives you the Witch effect. The Broom effect is functionally a mix of ''YumeNikki''[='=]s Witch and Bicycle effects, and can be used to activate a special flying event in the rainbow maze area, similar to ''YumeNikki''[='=]s Flying event.
** The FC world's glitch event heavily resembles ''YumeNikki''[='=]s, down to having to interact with a wall in a dead end room.
** Outside of ''YumeNikki'', the Broom effect gives Sabitsuki [[KikisDeliveryService a large red bow and blueish dress]].
** The seedy Psychedelic Town and Sweet Sugar hotel accessed near the Rainbow Maze resemble ''Videogame/{{Earthbound}}'''s Moonside.
** Smile's cross tattoos resemble a lot of a certain [[DoroheDoro cross-eyed gang.]]
* SlasherSmile
** Nearly every single mouth (and there are many) in the game, most notably Smile's.
** The twintail Kaibutsu is sometimes interpreted as having one of these; the Sabitsuki Kaibutsu definitely has one of these.
** Looking closely at her sprite, Rust seems to grow a deformed one as she becomes more and more decayed by the red demons.
** The Sabitsuki in the school you get the School Uniform effect from has nothing but a creepy smile on her face. And then you hear the Kaibutsu laugh upon exiting the room...
** During the Bloody Room event, after coughing up some blood, Sabitsuki smiles creepily before collapsing.
* SnowMeansDeath
** The Industrial Snow area has a few of these:
*** It is where the Dress effect is found, with said dress resembling a black funeral gown.
*** There is a special plant in a building which, when interacted with, makes the area overgrown with vegetation and makes it loop.
*** Blowing the whistle in the snow area reveals a ghost of a younger Sabitsuki wearing a scarf.
** Some theories speculate that the snow world is really a cremation site, given the smoke stacks and the Plant Labyrinth below resembling a tomb, and with the snow actually being ashes.
* SplitPersonalityTakeover: It's speculated that some version of this happens in the third ending and the events leading up to it. Usually Rust is the one doing the takeover.
** SplitPersonalityMerge: That, or this happens, given how blurry the line between the two identities becomes.
* SurrealHorror: There are just so many strange and seemingly nonsensical creatures that appear to have no purpose that you can't help but feel uneasy.
* SwallowedWhole: How one gets to the Rainbow Maze via the Footprint Path: walking right into the belly of a multi-eyed red monster.
* ThemeNaming: Another fangame character with a "-tsuki" in their name, though in Sabitsuki's case it means "covered with" rather than the usual "moon".
* TheMirrorShowsYourTrueSelf: Looking in the mirror in the Sweet Sugar washrooms as Rust shows an image of a horned, bleeding Rust in the reflection. Pressing the action button shows an image of Rust bleeding from the forehead, even if she hasn't been hit by red demons up to that point.
* TheVirus
** Parts of the game heavily imply that Sabitsuki had or currently has a fatal disease or virus.
** The red demons are speculated to either be a virus or a product of a virus, especially given their presence in the body areas and in the endgame.
** The Kaibutsu are speculated to be one as well, mostly by the asylum areas and [[spoiler:the implications that Sabitsuki may be becoming one herself.]]
** Interacting with a green cube in one of the Music World's inescapable areas will turn the rest of the [=NPC=]s into green cubes that only emit static when interacted with.
* TooManyMouths
** The mental world is filled to the brim with various mouths and toothy smiles, usually bloody.
** The red demons have a mouth on their stomachs and have one covering their entire face.
* TheUndead: The Corpse effect makes Sabitsuki a walking one. Pinching her cheek to wake up with this effect on makes Sabitsuki [[{{Squick}} pull her head into an awkward, possibly broken angle]].
* UnexpectedShmupLevel: The flying event accessed in the rainbow maze, a homage to the similar event from ''YumeNikki'', which has a different movement style to the one used in the rest of the game.
* UnlockableContent: All the various menu types.
* VideoGameCaringPotential
** The room before the Dying Girls event is full of [=NPCs=] blocking the path. You can either get through by killing the [=NPCs=] with the pipe, or with skillful manipulation of the whistle. While using the pipe can net you money -- indeed, this area is used as a place for farming money due to the sheer amount of [=NPCs=] -- using the whistle is by the far the faster option.
** The aforementioned Friendship Meter, involving Oreko.
** Interacting with Oreko with the Diving Helmet effect on and eating at the Sugar Hole both decrease the Erosion Counter by several points each.
* VideoGameCrueltyPotential
** The iron pipe, Sabitsuki's equivalent to Madotsuki's knife, can be used to kill things, and there are oh-so-many defenseless [=NPCs=] out there to beat to death.
** Raising the Erosion Counter involves making Sabitsuki experience incredibly traumatizing events over and over again, horrible enough that she gets disconnected from the mental world and leaks blood all over the floor and walls of her room, eventually revealing that she [[spoiler:has life-support devices attached to her computer]]. Just to rub salt in the wound, all you get out of raising the Erosion Counter to high levels is a new menu type and a very creepy event.
** Going between either versions of the Plant Labyrinth requires one to either enter the areas by different entrances in the mental world, or open up a usually-blocked door that acts as a gate between the two. Said door is opened by killing an [=NPC=] in either area. Do the math.
* VideoGameCrueltyPunishment
** The same kind as present in ''YumeNikki'': Trying to kill a Kaibutsu will just enrage them and make them chase Sabitsuki.
*** Trying to kill the Kaibutsu in the bar will just get Sabitsuki killed herself. As an added note, swinging around your pipe at everything may result in some serious consequences. For example, smacking a Kaibutsu in a specific foggy area accessible via the body area will [[spoiler: turn the whole place rusted and horrific]].
** The aforementioned Friendship Meter and Oreko. If you choose to kill Oreko several times, eventually she will disappear from the mental world, leaving only her diving helmet in her home. One can raise the Friendship Meter again, however, through interacting with the diving helmet.
*** Beating Oreko to death will also permanently enrage all the Kaibutsu until you raise the Friendship Meter again.
** Depending on how you interpret the event, the Nightmare event could count as this, seeing you have to raise the Erosion Counter to 250 points to get it, and the painstaking process and trauma you have to put Sabitsuki through to get it that high.
** Piping all the guitar-playing [=NPC=]s in the Underwater Village turns the place dark and makes all the other [=NPC=]s come after you, and getting caught transports you to an inescapable area in ''Hell''.
* WeatherControlMachine: The Watering Can effect makes it rain (or snow, if used in the Industrial Snow world) in varying degrees, from a slight drizzle to a downpour. A special event in the Psychedelic Town is activated with the use of the watering can, and one can put out Charlotte's fire by summoning rain.
* WholeEpisodeFlashback: The general consensus is that version 0.16 counts as this, depending on just how much of an AprilFools joke you take it as. It attempts to explain how Sabitsuki's time at the hospital as a child was.
* WombLevel: One area is made out of flesh, with a few rooms shaped like organs, and the area's music contains a slow heartbeat. Disturbingly, it gets more and more obviously decayed and diseased as you go deeper in.
* YouGottaHaveBlueHair: While most [=NPC=]s have either white, black, or brown hair, there is Charlotte, who has pink hair.
* YouWillBeAssimilated
** In the endgame, if Rust is hit by enough demons to the stage before death, looking closely at her sprite reveals that she appears to have a set of horns like the demons' through all the blood and gore, raising this implication. It's also worth noting that she grows a SlasherSmile as she becomes more and more deformed...
** In Rust's Corrupted School event, [[spoiler:some of the Kaibutsu get transformed into the giant red demons]], complete with screams of pain heard nowhere else in the game.
** To a lesser and far more subtle extent, the Kaibutsu seem to be this to humans, through some sort of disease or bodily experimentation. [[spoiler:The third ending strongly implies that Sabitsuki has, or is becoming one herself.]]
* YourHeadASplode
** Attempting to enter the Bloody Room before the endgame will cause Sabitsuki to shake her head and refuse to go in. When you then try to leave the area, she falls to her knees, coughing up blood as her head bleeds profusely and falls apart.
** After you become Rust, this happens if you bump into too many red demons.
* YourMindMakesItReal: There are a number of events can affect the real world. See the Erosion Counter detailed above.
* YourRewardIsClothes
** A number of effects are simply cosmetic and either have only little animations with no major uses, or simply do nothing. For example, the Dress effect makes Sabitsuki do a curtsy.
** A hut in the Underwater Village contains two dresses that Sabitsuki that wear. These dresses are simply cosmetic, however.

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