Probably the creepiest puzzle game ever, starring Irisu Kyouko, an asthmatic, mentally unstable university student with an obsession with rabbits, having gotten attached to one at school when she was young. She always had trouble socializing with others, and felt the class rabbit was her only friend. Unfortunately, it was horrifically killed one day, something that was discovered when Irisu found a cat licking the bunny's decapitated head, traumatizing her and causing her to hate cats.
The game also features three university students out on a camping trip: Edogawa, a Genki Boy, Age Hatori (Ageha), a cat obsessed Genki Girl, and their friend, the perpetually dopey looking Uujima (Uuji)note . Later in the game, it reveals that Irisu not only came on the trip with them but planned the entire outing. Edogawa tells his friends of a witch that lives in the forest, although the other two don't believe him. Later that day, he does not return after going out to fish. Uujima and Ageha search the forest to look for him, when Uuji hears something. He goes by himself to examine it, but he does not return, leaving Ageha alone, possibly with a witch preying on her.
The updated rerelease, Irisu Syndrome: Metsu, expands on the story and explains the motivations. It turns out that a younger Uujima was the one who likely murdered the bunny, in a particularly terrifying instance of Insane Troll Logic — eventually, the rabbit would die, which would leave Irisu sad and lonely. So instead, he brutally killed it, accidentally leaving its head to be found. The theory was that the combination of not having the bunny around to hide with and the pity she would receive from the event would encourage her to gain friends. Instead, she happens upon the bloody scene and a kitten lapping the blood up, causing her to snap and stop coming to school.
Meanwhile, Uujima grows up, forgetting about Irisu and generally growing more and more dangerous. He has taken to drawing countless hundreds of pages full of cute kittens killing themselves in horrific ways, also mutilating his arms to remember the bunny. Irisu, now a college student, notices his drawings and believes this makes him her soulmate, due to the fact that she hates cats ever since the above events. She falls for him but never speaks to him, while Edogawa and Ageha attempt to reach out to Uuji after Uuji takes a swooning Ageha somewhere she can rest.
Unfortunately Ageha rather obviously falls for Uuji, and Edogawa and Ageha keep Uuji so busy he can't draw his cats. This prompts Irisu to start plotting to kill them so she can have Uuji for herself. Uuji has noticed Irisu looking at his notebook by this point, and has fallen for her himself in his own twisted way. He decides to start looking at her notebook, discovering her "plan" — she is going to help Edogawa with a birthday party for Ageha, where she will murder both of them. He realizes her plan would only get him in trouble with the police, and decides he wants her to murder him, too, out of a twisted sense of romance. Ageha, becoming close to Uuji, confronts him about the cat drawings. He makes the excuse that he is imitating "The Book of Bunny Suicides," a foreign comic. She makes an offhand suggestion that leads him to a great idea — Irisu loves rabbits, so instead he'll draw pages of bunnies hurting themselves.
Once the four of them are alone on their trip, Irisu launches her plan. Edogawa is the first victim, then Uuji and Ageha go off to look for him. Hearing something, Uuji wanders off on his own and vanishes. Ageha is left behind at the campsite, alone.
This is where the story breaks apart depending on your score.
The game you are playing is one Irisu uses to keep herself sane. If you consistently score under a certain number of points, the game over pictures start to show her crying. If you haven't reached the required score before this point, you will get the bad ending, a news report talking about police identifying Edogawa's corpse.
If you manage to get the good ending, you see Ageha inside the building. However, Irisu, in a horrifying fourth wall breaking scene, comes from outside the game (As in she walks across your fucking desktop and into the game window!) with a nailbat, attacking her. The game then closes itself.
Afterwards, when you re-open the game, you discover that the sounds of horrific murder were actually Edogawa with a noisemaker, and the nailbat was a loaf of bread — in the bad ending, Irisu was murdering people with one of her kneesocks filled with rocks, a makeshift blackjack. By getting enough points, Irisu was able to keep herself from making a horrible mistake and instead went through with the "surprise party" plan she had presented to Edogawa and Uuji. However, once Metsu mode is unlocked, Ageha's picture in the game folder gets whited out, and a new text file implies that Irisu still plans to kill Ageha.
Two bonus details hint at even darker things — every time you score over 40,000 points in the original mode, you see the picture above instead of the usual game over picture. If you manage to reach 100,000 points in the old mode before playing Metsu mode, you get a drawing of the suicidal bunnies,
with a big black Madness Mantra X drawn through them, a red explosion above them, and the two dark black with red irises under them all with a rabbit with messed up eyes and one of its ears exploding blood appearing from the bottom of the page! The insinuation to both stingers is that by taking enough time, she has figured out it was Uuji that murdered her rabbit, and/or that she found the drawing of the bunnies after previously giving up on the plan, and/or that there's some other influence (the glowing red eyes — i.e., the spirit of her murdered bunny, demanding revenge) causing the events of the series.
In the final ending gained by playing through Metsu, Uuji doesn't let Irisu see the drawing of the bunnies, leading to an even better outcome — Irisu and Uuji are now good friends with Edogawa and Ageha, a situation that even Uuji is content with. Reaching level 100 in Metsu mode will also cause Irisu to smile in both the game over picture and Metsu title screen, a far more optimistic reward than the normal mode stingers.
This game within a game provides an example of:
- Alice Allusion: Irisus name is a reference to Alice- see Meaningful Name below.
- All There in the Manual: Many, many things can only be read in the text files the game creates in your game folder as you continue to play the game. One, called irisu.txt, consists of just three vertical dots. A couple of the text files, including full profiles of all four characters, can only be found by extracting them from the data library (see Dummied Out below).
- Anti Poop-Socking: Inverted. Go ahead, try to click away from the program and see what happens...but only when the game feels like it. It will only happen once, and only after you have played at least 12 rounds.
- Irisu. But averted in the good endings, where Irisu is able to calm down.
- Meanwhile, Uuji is more of The Sociopath.
- Batter Up!: It's actually bread. Irisu murders people with a sock full of rocks, not a bat.
- Big Bad: Irisu seems to be this at first, but its actually Uujima who is pretty much responsible for the plot (though its also implied that U-tarou is influencing Irisu).
- Bullying a Dragon: Intentionally done by Uuji, accidentally done by Ageha (she tells Irisu off during the good ending for basically stalking Uuji).
- Break the Cutie: Irisu.
- Cats Are Mean: Irisu thinks so. She hates cats more than anything else after seeing a cat lick the blood from the school rabbit's severed head. The game doesn't really hint whether this trope is truly in play or if the cat was just following its instincts. There may even be a bit of an aversion, as the cat and rabbit apparently got along just fine while the rabbit was alive and would even play with one another through the fence.
- Death Seeker: Uuji purposely plans to set Irisu off so she would kill him.
- Demonic Possession: Heavily, heavily implied to be the source of the above images and the ultimate cause of everything. The spirit of the bunny isn't happy that Uuji got away with murdering it, isn't happy that it was forgotten, isn't happy that Irisu's being mistreated... The Stinger is named U-tarou, just like the original bunny, too.
- Driven to Madness: A horrifically realistic portrayal.
- Dummied Out: Several hidden text files and images were included in the game's data files but never referenced or unlocked. These include profiles, character design sketches, and Irisu talking about the block-destroying game that she plays to keep sane. The filename? uutaroutherabbit.txt.
- Dysfunction Junction: Irisu is seriously messed up, but you find out later that Uuji is infinitely worse.
- Earn Your Bad Ending: The final unlockable in normal mode implies that Irisu found the suicidal bunny pictures and became mad again. However...
- Earn Your Happy Ending: The game is something Irisu plays with herself to keep calm. Score below 20k, and she'll end up going berserk and most likely killing everyone. Score over 20k, and she'll tear right through the 4th wall to attack Ageha anyway... Except it turns out the whole thing is just a really weird surprise party setup by Irisu. (Although it's heavily implied she goes after Ageha anyway). Score over 50k in the new New Game+ Metsu mode, and Irisu will start dressing normally, and the ¡Three Amigos! — now Four Amigos — will pose for a picture.
- Arguably, also the case when you reach level 100 in Metsu. The smile she gives the camera is sweet and genuine.
- Endless Game: Normal mode goes on for as long as you can endure. Metsu mode ends at level 100.
- Evil Albino: Irisu. Averted in the best endings... maybe.
- Evolving Title Screen: When you get the good ending, wait long enough and the background will begin to go much faster before it turns into a description of the events where Uuji murders U-tarou, written by Irisu herself. The next change happens if you unlock Metsu mode, where it shows the decapitated head of a cat on the bottom right corner of the screen. Clicking on it takes you to the aforementioned mode, which also changes the title screen via changing the logo to a dark red version with a darker background while Irisu is walking with her back turned. The Album option is also gone in this mode. The final change occurs when you reach Level 100 on Metsu, where Irisu is shown smiling and looking towards the screen, and the same description from before is in the background.
- Falling Blocks: And rising blocks. And in Metsu, bubbles.
- Flashback Cut: When you unlock Metsu mode for the first time, a quick series of frames depicting the cause of Irisu's insanity appears before some exposition.note
- The Fourth Wall Will Not Protect You: In the "Good Ending", Irisu proceeds to walk in to the game window FROM THE SIDE OF YOUR DESKTOP.
- From Bad to Worse: Metsu mode. Turns out Irisu's not the only insane person. Presumably the 100k stinger from normal mode will still affect Irisu after the end of Metsu mode. Uuji has settled for a happy ending — he's getting Ageha and Edogawa together, Irisu has calmed down and has joined the circle of friends, everything is ok, right? ...unless Irisu happens upon the notepad he wrote in middle school confessing to murdering her bunny, or finds the bunny-suicide image that he intentionally created to drive her insane. Not only that, she appears to have drawn a demonic bunny on the image. With blood on it.
- Game Full Of Crazy: Even without being able to read the story, you can still get a vibe that there's something just not... right about everything. The background has an albino bunnygirl who is never mentioned in the cutscenes, there are horrific pictures of suicidal cats in the background, the music is downright haunting, and in certain situations, the background of the main menu is replaced with millions of lines of Madness Mantra.... And god forbid you get the "good" ending without understanding it.
- Game Over Woman: Irisu. The picture above being an example out of six versions.
- Girl with Psycho Weapon: Irisu and her nail bat , which is actually bread. ... Her real weapon in darth bunnygirl mode is a sock full of rocks that she was planning to murder everyone with, the one she's holding in the title screen pictures.
- G-Rated Drug: Irisu becomes addicted to a cough medicine containing codeine and ephedrine, a presumably effervescent "white powder" she eats straight from the packet. By the diary entry describing her habit, she's up to thirty a day.
- Guilt-Based Gaming: See the Anti Poop-Socking example above. It's not nice to break Irisu's focus. Also, not scoring well enough in the first part of the story will eventually cause Irisu to cry...
- Guest Fighter: She shows up in Nijikaku, her style based from Fist of the North Star. Alongside that, she has a Humongous Mecha she had built all by herself, and has her own original moves as well.
- Hikikomori: It's insinuated that Irisu was this between middle school and college, to the point that Uuji, who went to middle school with her, doesn't remember her.
- Insane Troll Logic: The worst part of Uuji's descriptions of his decisions is that you can almost... almost see the logic. It's almost... almost logical.
- Interface Screw: See the Anti Poop-Socking example above. Also, the first part of the normal ending.
- Just One More Level: Gone Horribly Wrong. If you reach 40,000 points or higher and then finish the round, you get the crowner image above. With no warning. It's even worse if you alt-tab due to the randomness.
- Kindhearted Cat Lover: Ageha adores cats, and other characters mention once or twice how she reminds them of a cat. Including Irisu.
- Loners Are Freaks: As explained in Metsu mode, surprise: It's not Irisu. It's Uuji — the second to vanish and the one with half closed eyes. He's a psychopath who draws pictures of suicidal cats for fun, and it's heavily insinuated he killed Middle-School!Irisu's rabbit because he didn't want her to be... lonely. You know, in case it died? He then discovers Irisu's plan to murder the other two so she can be with him and tries to find a way to get her to murder him as well.
- Irisu as well, but she went the other way around — She was normal, but shy — until the traumatic events with the bunny.
- Love Makes You Crazy and Evil: The events of the game were touched off when Irisu got jealous of Uuji gaining (unwanted) friends, and decided to murder them.
- Love Triangle: Edogawa has a crush on Ageha, who is hinted at having a crush on Uuji, who is in love with Irisu, who is in love with Uuji.
- Man Behind the Man: Uujima turns out to be deliberately manipulating Irisu into killing him and his friends.
- Maybe Magic, Maybe Mundane: There are hints that the murdered rabbit's spirit could be responsible for the events of the game, but these hints are faint enough that a totally mundane explanation also works just fine. As mundane as the story can be, anyway.
- Meaningful Name: "Irisu" is just one syllable off from, and a slight mispronunciation for, "Alice". You know, white rabbit? There is also a real disease called Alice in Wonderland Syndrome. (Automated translators such as Babelfish and Google Translate even change "Irisu" to "Alice".)
- Irisu's name is composed of the characters for "enter" and "a nest". Kind of fitting for all the insanity that takes place.
- Mind Screw: Subtle, but it's there. Text files appearing, pictures being modified, background wallpapers changing...
- Multiple Endings:
- Bad Ending (Lose 6 times in a row): Irisu snaps, killing the 3 protagonists. The ending is of Irisu sitting in her room in the dark, listening to a news report about Edogawa's body being found.
- Good ending (20,000+ points): Irisu calms down, and instead of killing the 3 protagonists, she convinces the men to "disappear" and comes back to scare Ageha (AND THE PLAYER) witless. However, after a fourth wall demolishing scene, it turns out it was all just a birthday party for Ageha. Irisu and Ageha have a heartfelt discussion. (It's insinuated she still has major issues with the cat-obsessed Ageha, given the fact that she ends up erasing her face from the photo between this and Metsu.)
- Original Stinger: Get 40,000 points in Irisu Syndrome after getting the good ending to unlock Metsu mode. You get a new text file. Ageha's image is whited out.
- Extra Stinger (100,000 points in normal mode before playing Metsu): Irisu finds the bunny suicide picture, presumably after the good ending. She scribbles a demonic bunny on it, with glowing, hate filled red eyes. It is titled U-tarou.png, the same name as her killed bunny. It is possible that she went insane again after seeing this, and that the three friends are screwed.
- Metsu ending (Get all of the journal entries on Metsu's title screen, then get 50,000 points in Metsu): Uuji decides to work his best at getting everyone together, although he's not sure he is happy with the situation. Ageha and Edogawa are starting to fall for each other, and with his help, Irisu has joined in with the group as a new friend, and Edogawa and Ageha are now performing their "no Hikikomoris allowed" policy on her. It's insinuated that someone — Uuji or Irisu — found Uuji's journal about the bunny, but this has little effect on the overall plot.
- Murder the Hypotenuse: Irisu's plan for Ageha and Edogawa. Uuji's plan for... himself. Unfortunately, the latter combined with the former equals Ax-Crazy fun... maybe.
- New Game+: Beating the game unlocks Metsu (aka Destruction, Ruin, Doom...) mode, which plays hell with the rules. New bubbles float up from the bottom, which supplement the rubble on the ground. In addition, you can no longer launch trash out of the screen to get rid of it. Major story explanations are also given as you play through Metsu Mode.
- Nightmare Fuel Coloring Book: Uuji's suicide drawings, even though he's in college.
- And the unlockable scribble picture you get for reaching 100,000 points on normal mode.
- Non-Indicative Name: The word "Metsu" means various negative things as mentioned above and this mode has a darker feel, but playing through it only gets you explanations and good outcomes for the story.
- Nothing Is Scarier: The only thing more pants-wettingly terrifying than the music during the good ending is when the music stops.
- Irisu.txt, the text file describing her. ...
- Oblivious to Love: Horrifyingly subverted. Uuji recognizes Ageha has a crush on him, but is annoyed by it more than anything else, recognizes Edogawa is in love with Ageha and wishes he'd take her away, then realizes that Irisu is in love with him and she's completely out of her gourd... which he finds cute.
- Oh, Crap!: The Stinger. Look closely at the dead rabbit's eyes — they're red. Look in the lower part of it? See the red-on-black eyes? Why do those keep coming back?!
- When you see what it really is you will excrete building materials. IT'S A GODDAMNED DEMONIC BUNNY.
- Fridge Horror When you read through Uuji's diary, you read that one of the ears of the original bunny was damaged. Right about where that big, red X is on the note. To say nothing about the random bits of blood in the corner. And the filename? It's the same name as the pet bunny.
- When you see what it really is you will excrete building materials. IT'S A GODDAMNED DEMONIC BUNNY.
- Out, Damned Spot!: While not outright confirmed, mention of how "he'd remember the bunny by the bruises" and how Uuji never wears short sleeves suggests that he's been self mutilating himself for years... after otherwise forgetting the bunny incident.
- Painting the Medium: Text files appear in the program folder, and a picture is modified to reflect the story progress. One of the endings has an awesome example, see Interface Screw above.
- Pair the Spares: In the best ending, Uuji decides to try to get Ageha and Edogawa together, since they make a much better couple than Ageha/Uuji, which also leaves him available to date Irisu. Of course, since he's a nutjob... This may or may not work.
- Prophetic Fallacy: One of Irisu's classmates in middle school — heavily implied to be Uuji — had a vision of the class pet rabbit dying of natural causes, leaving Irisu sad and alone. So instead he murdered it, accidentally leaving its mutilated head out in the open for it to be found. The idea was that Irisu, who was taking care of it, would be approached by everyone out of pity when the rabbit "vanished" and she would make friends. In reality, not so much...
- Puzzle Game: Really, really HARD, at that.
- Reality Ensues: In Uuji's txt. entry, he discovers Irisu's plans to invite him, Ageha and Edogawa on a trip, murder the latter two and erase the evidence that she was there. In his entry, he points out that even if the plan was carried out successfully, he'd still have to tell the police something.
- Red Eyes, Take Warning / Black Eyes of Evil / Glowing Eyes of Doom: Oh boy, just look at that screenshot up there. (Obtained for hitting 40,000 points after seeing the other endings in normal mode, or automatically at level 100, which also ends the game immediately.) They also randomly appear after you've played the game 13 times upon alt-tabbing... but only once. And this is never explained or mentioned again.
- The Reveal: Let's explain just how Metsu altered everything players thought they knew. In the original game we learn that Uujima is the unfortunate victim of Irisu's affections, and only because he draws pictures of cats dying in gruesome ways, which he claims he's only drawing in the first place because he's trying to imitate an actual European cartoon book. When we see the 100k picture we assume that Uuji followed Ageha's advice and drew a picture of rabbits dying, that Irisu happened to find, with predictable results.
- Now then, once Metsu came out, it revealed that Uujima is the real Big Bad; he knew about Irisu's affections, he knew that Irisu wanted to kill Ageha and Edogawa, and he purposely drew the picture of the rabbits dying so that Irisu would kill him! Not to mention it's implied he's the one who killed the rabbit Irisu took care of in her childhood, making her the messed up person she is today Did anyone expect this?
- Scary Surprise Party: Subverted. It was Irisu herself who planned the "party" for Ageha, intent on using it as a cover to kill Uuji's new friends so he'd go back to drawing suicidal cats. In the best ending, she simply decides against it and plays along.
- Once you unlock Metsu mode though, Ageha's face on the photo gets whited out...implying Irisu still has bad intentions for her later on. Metsu's ending fixes this.
- Scoring Points: Needed for Unlockable Content. Over 40k on normal mode unlocks a nice new game over screen, as well as Metsu mode itself.
- Secret Level: Achieving 40,000 points or entering a code unlocks Metsu mode, which changes the way the game is played. Needed for the true good ending.
- Said code is "up 4 times, right 2 times, down once" on the title screen, which is hidden on Uuji's coat.
- Sequel Hook: Uuji's commentary during the perfect ending in Metsu suggests he's not 100% happy with how things turned out, even though it's pretty close to a perfect ending for everyone. And there's no explanation of the "red iris on black eyes" theme that appears on Ax-Crazy!Irisu, the picture Ax-Crazy!Irisu defaced in The Stinger, and in Uuji's nightmares.
- Mentions of Irisu Syndrome Kai (aka Irisu Syndrome: Solution) are sometimes thought to be confirmation of a sequel, but it turns out Kai was just the working name for Metsu.
- Slasher Smile: If you look closely at the top of this page, Irisu seems to have one. It's actually her chin, but since it certainly looks like a smile with that coloring...
- Stalker with a Crush: Irisu is convinced that she and Uuji are soul mates because she chanced to see some doodles on his notebook, depicting cats killing themselves in various ways. Uuji reads in her diary/notepad that she feels their relationship is going forward quite well despite them never speaking to each other.
- However, Metsu reveals that Uuji has also a stalker-like crush on Irisu, filtered through his own personal insanity: He finds out she wants to kill his friends, and wants to try to get her to kill him, too.
- Start of Darkness: Metsu mode serves as this for Irisu and, to a certain point, Uuji, explaining what happened with the bunny and the "plan", and so on.
- The Stinger: Multiple. All creepy as fuck.
- After getting the good ending of the original game, the background of the main menu is replaced with Madness Mantra scrawl after a certain amount of time has passed. (Randomly, approx one in 2 chance. Can be forced by holding down spacebar, which causes the game to run at max speed.)
- After the good ending, get 40k points on normal mode and Ageha's picture gets whited out — oh, and you get that lovely picture at the top of the screen when the game ends, implying that even with the day going perfect, she snapped later anyway.
- Get 100,000 points in normal mode before playing Metsu and there will be a new picture in the game folder, of "Bunny Suicide" doodles... which Irisu apparently found. It's splattered with blood, the tortured bunny has had glowing red eyes drawn on top of it... and Irisu has drawn a demonic bunny coming out from the bottom of the page, with glowing, insane eyes.
- Getting to level 100 in Metsu Mode causes Irisu on the title screen to start smiling, and the round to end immediately with the same ... not quite Slasher Smile. Two fan theories on that — Either she's finally happy and sane-ish, or she's gone completely postal. Fortunately, no more red eyes-on-black images appear after Metsu.
- Shout-Out: Edogawa always wears a shirt with a design on it, each design referring to another game by the same creator. The one he wears during the camping trip is a rendition of the Mother 2 logo reading Ma Mo Mo (short for Maou Monogatari Monogatari). In the "photo" in the game folder, his shirt shows the characters from Ototsukai, while another shirt in the Metsu ending references Ai to Yuuki to Kashiwa Mochi.
- The game appears to reference the Suicidal Bunnies books by Andy Riley, though he's only referred to as "some foreign cartoonist called something-or-other."
- There are a surprising amount of these hidden throughout the game - in fact, a couple of the cat suicide pictures in the background make no sense until you have played Ma Mo Mo.
- Shrinking Violet: Irisu. An attempt to cure her of this by murdering her pet rabbit, accidentally leaving the head for her to find causes the events depicted in the game.
- Spooky Photographs: The game comes with a picture of the three amigos in the game folder, completely unexplained. As you progress through the game, the picture is altered. After Edogawa goes missing, his face is scribbled out with black marker. After Uuji goes missing, his face is scribbled out with black marker. If you get the bad ending, then Ageha's face will be scribbled out as well. If you get the good ending, the picture will return to normal. That is, until you score enough points to unlock crucial parts of the story, after which Ageha will be whited out of the picture. In Metsu Mode getting 50,000 points (triggering the "4 Amigos" Metsu good end) will cause the picture to return to its original state.
- Worse is The Stinger. You get a picture of tortured stick figure rabbits, the drawing Uuji used to send Irisu over the edge in the bad ending... only with a BIG black X marked through it... Which, if you zoom out and look it from a distance, makes it actually a drawing of a giant, demonic bunny. This is found only after the "good ending" appears — when Irisu is supposedly sane(r)... Meaning she found it after previously abandoning "the plan"...
- Surprise Creepy
- There Are No Therapists: It's unknown if Irisu got therapy after what happened in middle school, but given the fact that the game takes place in Japan... she was probably left to her own devices instead. Also no word on if Uuji was getting help, but Ageha does call him out on his creepy cat drawings once she feels comfortable enough around him. This turns out to be a very bad idea.
- ¡Three Amigos!: Edogawa, Ageha, and Uuji. And in the ultimate ending of Metsu, Irisu joins them.
- Big Bad Friend: Uuji. He started the events by murdering Irisu's rabbit. His reaction to discovering Irisu is plotting to kill his friends? Find a way to get her to kill him, too.
- Visible Silence: Irisu.txt. Just three vertical dots.
- Widget Series: Of the "OH GOD WHY" variety.
- When She Smiles: Irisu gives a sincerely happy smile when level 100 is reached in Metsu mode.
- Wham Episode: Metsu. Before its release, the game had very little explanation, just that Irisu was staring at the screen, occasionally went batshit insane, and the two endings switched between her murdering everyone and her NOT murdering everyone. Metsu unveiled the rest of the story.
- Why Did It Have to Be Snakes?: Cats in Irisu's case, due to her happening upon her pet rabbit's decapitated head being licked by a cat. Her seeing Uuji's "The Bunny Suicides with kittens instead" drawings is what causes the events in the series. Also used by Uuji as a form of suicide — he switches from drawing cute cats killing themselves to cute bunnies killing themselves in order to get her to murder him, too.
- Yandere: A rare two-way example. Irisu is insane due to her pet rabbit being horrifically murdered; Uuji is an apparently natural psychopath who wants Irisu to kill him out of some sort of twisted sense of romance... and who killed said pet rabbit out of some twisted kindness. Both are, at first glance, perfectly normal, albeit somewhat shy.
- Your Princess Is in Another Castle! / The End... Or Is It?: The best endings. In both of them, there are additional — and very creepy — things to find by playing the game further, hinting at another expansion.
I wonder where everyone went...: