Yume Nikki is a strange, unknown game that has been increasing in popularity which no dialogue and a unique art style. So, of course, fans have created many theories, some good, some bad, some complex and some that make us laugh. This article categorizes the theories by players and fans.
It's also worth noting that TV Trope's Wild Mass Guessing page on Yume Nikki contains a wealth of theories too, some of them more fleshed out versions of the theories seen here.
Madotsuki
Madotsuki was raped.
In the game, it is seen and easily noticed that there is much evidence that Madotsuki was raped. In the Forest World, along a strange road, several creatures in the background with eyes watch over you where the last one's eyes follow you for a split second as you leave. Many speculare that these are ovaries, which adds support behind the rape theory. It is also possible that these eyes are connected to the pregnancy theory, since they could represent ovaries, it could mean that after her rape, Madotsuki is watchful of herself and worrying if she is pregnant or not. Other incidents with eyes include the Eyeball World and the Barracks where entering a certain shed can lead to a tunnel where eyes follow the player as well as another on the way to the Witch effect eyes in the trees follow the player. The theme of being watched seems prevalent in Madotsuki's dreams and could be speculated as her memory of being stalked before being raped.
Hands are also scattered throughout the game ranging from a large theme of one world to appearing a few times within another. Some examples being the staircase lined with reaching hands on the way to Seccom Masada-sensei area, sprouting out of the ground in the Eyeball room and at the White Desert. The room Uboa teleports you to, which has a nightmarish landscape where a monster with multiple hands grasps hills in the background, is reminiscent of groping to some players, which supports another speculation that unwated touching is also noticable in Madotsuki's dreams.
Another thing supporting the rape theory are the pictures on the walls of the waiting room in The Mall which seem to allude to sexual situations, specifically one which is seen picturing a crying figure with a phallus shaped object on or even in its mouth (pictured below, right). The other image that is also located in The Mall, next to the crying face picute has a provocative image of a frowning mouth that appears to be drooling. The fact that the Flute effect is found here, which can be seen as a representation of fellatio (oral sex) supports these allusions. This could also be a sign that Madotsuki was forced to perform acts that she found unpleasant, leaving some very deep mental scars which only supports the ideas behind the images and themes in the dreams.
Some say that Kyu-Kyu, a large colorful pole creature who is seen rubbing the banister of a stairway, is a phallic representation. The Knife and Cat Effects alter the speed of which Kyu-Kyu rubs the rail of the staircase, speeding it up with the Kinfe Effect or down with the Cat Effect (which could mean that the rapist used to be gentle when she indulged him and rough when she tried to reject/fight him). Full-Screen Events feature an event called FACE, which is achieved by going through a door right next to Kyu-Kyu. Some say it resembles a penis, fear itself, and/or static, or even the image of a vagina with the entrance held open with forceps, adding support to both the rape and pregnancy theories. Many fans speculate that the sequence in which the player stabs through a wall (which closely resembles a zipper), leaving something similar to along the lines of a bloodied hymeneal opening which is then followed by the seemingly benevolent phallic-shaped Kyu-kyu-kyun to then be followed right after by the terrifying FACE Event suggests a high relation to sexual assault as the main theory for some players.
A dread of pregnancy, possibly originating from being raped, can be interpreted from the Henkei Shita, whose shape resembles a pregnant woman who has lost her head. The Henkei Shita could be seen as either Madotsuki's fear of becoming pregnant, the actual pregnant body representing the pregnancy and the severed head possibly the fact she herself wants to never acknowledge it, or it could even be her psycological fear of herself already being pregnant taking form in her dreams.
Something else to consider, is that Nasu, or eggplant, is a symbol of fertility in Japanese culture.
As of all the theories, the sexual assult is currently the most well supported one and believed to be the most likely one.
Many other minor factors also play into giving support to this, such as Madotsuki's possible of fear going outside and/or meeting new people, caused by her fear of running into her attacker again. The fact that she seems to do very little aside from want to sleep as her main thing, which speculates she wants to escape reality due to the possibility that the assult happened only a short amount of time before the games events as well as the possible reason to why Madotsuki's television doesn't receive any channels is because she's afraid of the risk of hearing about the news of a rapist or even her own attack, making her relive it again in memories.
Madotsuki is pregnant or has had an abortion/miscarriage.
The deep background image of many of the places strongly resemble a fetus - this also connects well with the rape theory above. The thing hovering in the background has a feeling of being very distant, yet always present and inescapable, representing either a pregnancy which obviously takes the better part of a year to happen but can't be escaped or the idea of an abortion/miscarriage that is a tremendously heavy emotional event for any female.
Madotsuki lives in an apocalyptic world.
Madotsuki seems like a perfectly normal girl, albeit possibly being a Hikkikomori (a shut in). Yet her dreams are strangely terrifying and eccentric, and she acts like she has been there before, displaying almost no emotion. But this could also be either that she herself is so terrified of her own dreams she beecomes emotionally dead, making herself somewhat emotionally numb to the dreams, or that she herself is a Lucid Dreamer (someone who is fully concious in their dreams) and that she knows her dreams are just that so she's not afraid of them at all. That, combined with the fact that her apartment is the only one in view, she won't leave her home, her TV doesn't get any channels and her only source of entertainment is a Famicom game called NASU, it would seem that whatever is out there is worse than what is in her dreams (possible more speculation to the rape theory).
Also, as proposed in this video, there might be some kind of epidemy, or alien mutation going on that could be transforming everything into monsters, thus Madotsuki would be forced to, or she could choose to, lock herself up inside her apartment to try and stay safe, but soon she would finally start giving in, and decides to end it all by jumping off the balcony.
Madotsuki is Transgender.
Another theory born from fans is that Madotsuki is was actaully born as a "male" but identifies as a woman and lives and dresses as one. The characters found in dreams could be distorted versions of friends, family, and peers that have alienated or even cut off/disowned her after she came out as a woman. The psycho Toriningen could stem from Madotsuki feeling that her own body is working against her. The possible imagery of blood and female reproductive systems are signs of love and longing towards periods and female puberty while the phallic imagery could hint towards her hate for a penis and male reproductive organs, but they could also hint that when she came out as a woman, it was met with violence be it from her own family and/or friends or not. Some support is given to the Transgender theory from The Toriningen Party where it could mean that she is isolated from them due to her not being a "real girl" in their eyes where as well the psycho Toriningen could be classmates that shamed her into dropping out of school and locking herself away. She could have been raped by Cisgender men on coming out, as it is a common method of "teaching" a lesson in hate crimes.
The graffiti world to monochrome world path could actually tell a story about Madotsuki's transition from a boy to a girl. She wants to have the privileges and social status as a female (e.g. a women's toilet) so she flees from her masculinity (the bicycle) and begins to descend (the elevator). Many people fail to accept her who recognize her as the boy she once was (the mall people), yet her therapist gives her comforting advice, telling her everything is going to work out in the end (O-San). Eventually she starts to feel ugly (The Frog Effect) and isolated (lack of vocal comminication in the dreams), feeling that it will be a long, near impossible path to follow. (To be continued) The 8-bit world, which is passed through in the path, is usually interpreted as a representation of video games. Video game playing is often thought of as a masculine hobby, especially back in the 8-Bit and 16-Bit Era when video games were widely loved by boys. The entrance to the Monochrome world has limp phallus like objects hanging off the wall and an eye in front of a body of water. This could be related to her penis and crying, respectively. The monochrome world itself may be interpreted as a world of regrets, which would make sense why this would all lead to that world.
There is also a small possibility of Madotsuki actually being intersex. She could either have breasts, and female genitalia on the outside, with testes where her ovaries are meant to be, or she could have the male organs outside, and the female inside, which could explain why both female and male reproductive organs have such a horrific depiction in many areas of the game. Many intersexed people suffer from anemia caused by lack of appropriate hormones. This could explain, possibly, why it is that Madotsuki sleeps so much because she is lacking energy.
Madotsuki is a Lesbian.
Poniko is her image of a perfect beautiful girl she yearns connect with but can't because other girls she knew in the past weren't "weird" (gay) that way. She resorts to desperate measures to try and get Poniko's attention (going through different effects, flicking off the lights). Though she herself feels that her thoughts are dirty and she's afraid of the reaction others may have to her. That could be why Uboa, a possible manifestation of that fear and guilt, pops up. The signs that people interpret as rape (Kyukyu-kyun + Face Event, the hands and eyes scattered everywhere, the Henkei Shita, etc) aren't signs of a past rape trauma but a dislike of penis, distaste of being watched by men, fear of judgment, and fear that she too will be expected to get married and give birth some day.
Madotsuki achieves a happy ending.
A theory that proposes that Madotsuki was dreaming (or in a coma) all along. Her suicide at the end is the result of her finally coming to terms that nothing in the world is real and she has been trapped in a dream. She escapes by killing herself so she can jolt herself awake. This theory is backed up by dream creatures who surround her bloody smear in the "real world" after her suicide, the fact that her eyes are always closed, the surreal and ever changing landscape outside her apartment/house, her apartment having no kitchen or bathroom, and how she's unable to leave her room support this theory.
This is also further supported by the idea of a car accident. For example, the Henkei Shita, which appear to be decapitated could be a representation of her memory of someone dying in the car accident (possibly a pregnant woman or even her own mother who was carrying her unborn sibling) and Shitai-San could be another one of the victims from the accident. This could point to that Madotsuki is in fact not awake at all, but rather trapped in a coma, and her jumping off the building at the end of the game could be her waking up and becoming free from her coma.
This theory is popular with many fans as they don't like the idea of sad ending for Madotsuki.
Madotsuki is a representative character.
Madotsuki is by no means a common Japanese name; it refers to the fact that she has a window on her chest. The window was most likely chosen to become a "window" into the life of people who are antisocial, depressed, alone, disturbed, etc. Madotsuki's dreams portray many different views on depression and unhappiness. These different views are not meant to represent specific events in the fictional life of Madotsuki, but general events in the life of someone who is "different". The Toriningen Party could have represented a social status that a person could not reach, no matter how hard they tried. To some, a crazed Toriningen could be viewed as someone who is angered, and when the person tries to reach out to them, they are only cast out, which is shown by the Toriningen sending Mado to isolated and inescapable places. Poniko/Uboa could represent distrust and false friendships. The strange "people" in the Department Store have no face and refuse to speak to her, possibly representing how these antisocial people may view others. This game is far too abstract to be viewed as a simple and linear plot, so a representative theme would make much more sense. In a sense, Madotsuki is the poster-child for all children and adults who feel like they just don't fit in.
Madotsuki is a murderer.
Depending on the player's actions, Madotsuki can behave violently towards NPCs and sometimes inanimate objects. Given that she finds the Blonde Hair effect near a red puddle, maybe she killed one of her friends, and the puddle represents blood. Perhaps it was a killing along the lines of the Sasebo slashing. Madotsuki doesn't want to go outside because she feels remorse for her actions.
Something terrible happened to Madotsuki in the past.
Getting to Poniko is really hard, you have to go through a lot of places to get to her, which could mean she is locked away. Poniko could be interpreted as Madotsuki's emotional side, which, because of something either of a terrible sexual experience, or perhaps fear to grow up or lack of a childhood, Madotsuki locked herself away because of the fear and pain to confront. Poniko ignores Madotsuki, which could also mean that confronting what happenned is too painful for Madotsuki and Poniko. Bothering Poniko (switching the lights on and off) causes Uboa to appear. That could mean that Uboa is a revenge from Poniko, from not only leaving her locked-down and alone, but bothering her. Trying to kill Uboa leads Madotsuki to a place with a highly disturbing background, if analyzed well, could also mean a bad sexual experience. The FACE Event could be the result of trying to confront this event, meaning all the fear, pain and sadness, etc. Since she wakes up immediately, it means she failed in trying to confront it or just did it the wrong way.
Madotsuki has severe Hypertropia.
Hypertropia is, essentially, googly eyes in real life. Due to the way Japanese society works, her eye problems would draw a lot of attention and probably discrimination, leaving her a Hikkikomori and always keeping her eyes closed so it's not noticeable. The googly eyes that are more or less everywhere (including the place where Uboa appears) are her mental psyche reminding her of the fact. The black-and-white areas, which seem to represent her younger years judging by their art style, have occasional googly eyes in them as well. Masada, the most obvious example of googly eyes, is usually determined to be some part of Madotsuki's mind that she's trying to send off - in this case, her Hypertropia and possible other mental problems (see: autism; autistic people do not interact with other people very well, and are often precocious in areas such as piano-playing). In fact, there are eyes everywhere, googly or not; the unsettling sequence in the refugee town where Madotsuki walks past a long row of shacks with eyes on them, all staring at her, might represent her issues about eyes, or maybe feeling like she's being put on a pedestal to be examined and ultimately judged. Why she can see fine, despite her eyes not pointing in the right direction, is because it's a dream.
This theory also lends a little support to the Madotsuki achieves a Happy Ending theory, in which because she's constantly dreaming, even when she's "awake", when she jumps of the ledge at the end, it is the end of her dreaming, not her life.
Madotsuki's Dreams are her warped representation of School.
Madotsuki is a misbehaving child who steals things from other students, which could be represented by her need to find The Effects.
The Toriningen are representations of the teachers. Some teachers know that Madotsuki is a thief, and they try and stop her, these teachers are the lunatic Toriningen. When they catch Madotsuki, they send her to an inescapable place - her minds alteration of detention. Other teachers don't know about Madotsuki being bad, but they can be made be realize this if they see her do something bad. These teachers are the nice Toriningen who will become hostile when stabbed.
Poniko is the assistant principal or the office assistant. She doesn't bother Madotsuki because she doesn't have any say in it, or she doesn't belive that Madotsuki is really bad, or she simply doesn't care where as when she changes into Uboa, he/it can possibly be a representation of the schools headmaster and thus his trap world could be his office.
Seccom Masada-Sensei is, as mentioned before, her music teacher. He doesn't know about Madotsuki's violent behavior, which is why he runs when she pulls out the knife, hinting that even though the player can make Madotsuki use the Knife Effect, she herself doesn't want him to know about her bad/violent behavior, so in her dreams he always flees rather that allowing the chance for him to be stabbed.
Shitai-san can possibly be seen as either the drama teacher who is in a play where his character dies or a student who has died in a car accident.
Monoe and Monoko could be seen as sisters. Monoko is mentally disabled, so Monoe helps her by keeping her at home and teaching her on her own. This could explain why Monoko can be seen as a disfigured small girl and why Monoe doesn't say anything, even in her Full Screen Event.
Mars-san is an orphaned foreign exchange student.
The Dave Spector character could be seen as Monoe's ex-BF which is why he keeps her locked up, unless he is scared off.
The many characters might be her representation of students or other teachers.
Madotsuki feels very different from most people her age
Madotsuki feels very different from most people her age due to acting different than other people (being quiet all the time, never going outside except to go on the balcony, having a dream diary, etc.) and most of the people at school, including the teachers made fun of her for being "weird". The Toriningen are girls that made fun of her, Monoe is a girl who just laughed at her and runs away after doing so, Monoko was Monoe's little sister that multitasks often and doesn't eat that much (the hands representing the fact that she does many things at once and the hole in her stomach representing her hunger), Shitai-San is a student who died in a car accident, and E-Man and O-Man and the Toriningen in the mall are teachers that were mean to her. Masada is the music teacher of whom she is friends with and Poniko is her best friend who yells at her when she gets irratated.
The various worlds and locations in her dreams represent events in the real world and elements of her personality:
Number World- Having trouble in Math
Puddle World- A dark rainy day
Neon World- A school dance (the creatures there represent people dancing and having fun)
Snow World- A snowy day where people made igloos (maybe the Pink Sea is her remembering summer on that day?)
Dark World- A dark day where she got angry and depressed and found a knife
Forest World- Playing with her friends in the woods when she was little
Shield-Folk World- People wanting to stay away from her
Eyeball World- A representation of her creative side, using eyes and limbs as the main feature in most of her drawings
Graffiti World- Another creative side in which she has a fascination towards abstract art and music
Block World- Meeting a friend who's like her and exploring a city
Candle World- A power outage and having to put candles everywhere
Mural World- Beginning to take an interest in surreal art
The Mall- Taking an interest in the mall where everyone thought she was strange
The FC World- Remembering playing RPGs
Hell- Trying to avoid it or anything demonic
Cement World-Her idea of Heaven
Sky Garden-Again, her idea of Heaven
Barracks Settlement-Representation of her hometown
The Docks-Vacationing near the sea
Static Maze-Remembering TV static and trying to figure out how to make it stop
Aztec Imagery.
Aztec imagery appears in most backgrounds in Madotsuki's dreams and even her real life room (the carpet). It could indicate she may have a strong fascination towards Aztec culture. Maybe because of its fundaments or out of mere curiosity.
Perhaps it is symbolic: the Aztecs were hated by all people of all places before they settled in Tenochtitlan. Even when they reached the valley of Texcoco everybody tried their hardest to expel them from the proximities of the lake. Throughout their brief history as lords of this rich land they where known as dark, grim, suprahuman fighters with an intrinsic veneration to death, bodily sacrifices and motherhood as they had more than one deity that symbolized these elements that are so recurrent in throughout the whole game.
It may be that Madotsuki feels identified with these people, their culture, their art and what they symbolize as well as could be why she kills herself at the end, believing it to be a form of ritual self sacrifice that will free her.
Mars-san.
It is all alone, accompanied by nothing but strange "machines" and depressing music. It is also crying. Has Mars-san simply burst into tears because it too is trapped on this strange planet, and it's helpless? Maybe the machines are it's countless ways to escape the planet.
Could this be symbolising an element of deep and utter hopelessness, being trapped, and unable to escape? Not being able to escape not just Mars, but being that this is Madotsuki's dreams? Maybe this is a realisation that she is trapped in her own mind?
This can easily be put with other theories to suggest a possible reason why Madotsuki kills herself in the end of the game, because she can no longer stand being trapped in her own head.
Toriningen are trying to save Madotsuki.
The Toriningen might be aware of what happens when Madotsuki collects all effects, and they might be trying to prevent that from happening by teleporting Madotsuki away.
Madotsuki had a twin.
In the White Desert there is a 1 of 3600 Chance where "Takofuusen" (Octopus Balloon) will appear. Takofuusen looks a lot like a birthed twin with the twin reversed artiel perfusion or "TRAP Syndrome". Takofuusen could be Madotsukis twin but had the TRAP Syndrome. Other theories suggest that the White Desert is a place full of memories such as Monoe and Monoko. Takofuusen could be a memory of Madotsuki's twin.