Chaos;Head (stylized as ChäoS;HEAd) is a 2008 science fiction visual novel video game developed by 5pb. and Nitroplus. It is the first game in the Science Adventure series. Following the original Windows release, the enhanced version Chaos;Head Noah was released for Xbox 360 in 2009, and has since been ported to multiple platforms. An English localization is planned to be released by Spike Chunsoft for Nintendo Switch and Windows in 2022. The game follows Nishijou Takumi, who gets involved in the "New Gen" serial murder case. He frequently experiences delusions and hallucinations, some of which the player can influence, which affects the progression of the story.

A stylized illustration of a young woman with pink hair, wearing a school uniform. She sits by a futuristic sword-like weapon, which is flat on the ground, running diagonally across the cover. Running parallel with the weapon is the game's logo, saying "Chäos;HEAd" in large fonts. The background is entirely white.
Windows cover art, depicting Rimi Sakihata
Developer(s)5pb., Nitroplus
Director(s)Tatsuya Matsubara
  • Chiyomaru Shikura
  • Digitarou
  • Chiyomaru Shikura
  • Hayashi Naotaka
  • Ogami Keichi
  • Takeshi Abo
  • Chiyomaru Shikura
  • 5zizz
  • Isoe Toshimichi
  • Syntarou Jimbo
  • Ooyama You
SeriesScience Adventure
Platform(s)Windows, Xbox 360, PlayStation 3, PlayStation Portable, PlayStation Vita, iOS, Android, Nintendo Switch
April 25, 2008
  • Windows
    • JP: April 25, 2008
    • WW: October 7, 2022
    Xbox 360
    • JP: February 26, 2009
    PlayStation Portable
    • JP: June 24, 2010
    • JP: November 18, 2010
    • JP: January 24, 2012
    PlayStation 3
    • JP: November 22, 2012
    PlayStation Vita
    • JP: August 21, 2014
    Nintendo Switch
    • JP: February 24, 2022
    • WW: October 7, 2022
Genre(s)Visual novel

The game was planned by Chiyomaru Shikura and written by Hayashi Naotaka, and features character designs by Sasaki Mutsumi and music by Takeshi Abo, who described the game's sound as "rainy". The game was commercially successful, helping 5pb. establish itself as a game developer, and was well received for its story. In addition to the direct sequel Chaos;Head Love Chu Chu! and the thematic sequel Chaos;Child, manga, an anime series, and an internet radio show based on Chaos;Head have been produced.


Takumi having a conversation with Kozue. The delusional trigger system is displayed in the top left and right.

Chaos;Head is a visual novel game in which the player takes the role of Takumi Nishijou,[1][2] an otaku and shut-in, who experiences delusions.[1] The game is mostly linear, but frequently includes player choices:[2] the player is able to choose whether the hallucinations Takumi experiences should be positive or negative, or if he should manage to stay grounded in reality. Positive delusions generally involve comical or erotic scenes, while negative ones include horror elements and violence.[1] The player chooses the delusions through the "delusional trigger" system, wherein green and red lights are displayed on the top of the screen, representing positive and negative delusions.[2]

After the player has played through the game once, delusions chosen during subsequent playthroughs determine which of three endings they will reach.[1] When the player replays the game, they are able to fast-forward past passages of text they have already read.[2] In the updated re-release Chaos;Head Noah, further endings are possible to reach, also by choosing what delusions to experience.[1] The player can read about key vocabulary used in the game, including internet slang, through the "TIPS" glossary, which is updated with new items as the player encounters them in the dialogue.[2]


Chaos;Head is set in Shibuya, Tokyo.

The game is set in 2009 in the Shibuya district of Tokyo, where Takumi lives in a cargo crate on top of an apartment building.[1] He discusses the recent "New Generation Madness" ("New Gen") serial murder case in Shibuya with his friend Grim over the internet, when someone with the username "Shogun" sends Takumi image files depicting a man pinned to a wall with stakes. Later, Takumi witnesses a girl he does not recognize committing the murder portrayed in the image files, and he flees the murder scene. A few days later, she sits next to him in school. He thinks she will kill him, but is told that they supposedly have been friends for a year and that her name is Rimi Sakihata.

Convinced that Shogun is targeting him, Takumi tries to avoid getting involved in the murder case, which draws the attention of the police. As he becomes a suspect and more murders occur, Takumi worries that Shogun is targeting him and experiences paranoia and hallucinations, and becomes unsure of what is real and who he can trust. In one of his delusions, Shogun appears as an old man in a wheelchair and tells him that more people will die unless he awakens.

When Takumi sees a girl carrying a large sword in public and notices that only he can see it, Ayase Kishimoto – a student who recently transferred to Takumi's school – tells him that he needs a "DI-sword" to be saved. She makes such a sword materialize in her hands, and tells him about how Takumi, the girl carrying the sword – Sena Aoi – and her friend Kozue Orihara are Gigalomaniacs: people with the ability to project delusions into reality, which is called "real-booting".

The Nozomi Group, a technology company in Shibuya, is revealed to be using their Noah II machine to synthetically use Gigalomaniac power, and have staff carrying transmitters to increase Noah II's signal reach. When a Noah II-created delusion causes people to panic, Sena and Kozue destroy nearby transmitters, and Takumi, Sena and Kozue join forces to stop Nozomi. They infiltrate Nozomi's headquarters and reach an underground research facility where they find Noah II. When Nozomi's president Genichi Norose tries to stop them, they overpower him and destroy the machine, but it turns out to be a prototype rather than the actual Noah II, and the Norose they fought turns out to be a real-booted delusion projected by the machine.

Takumi learns that he himself is a projected delusion with fabricated memories: a copy created by Shogun, who is the original Takumi. His sister Nanami is held in the location of the real Noah II, where she is made to awaken as a Gigalomaniac and obtain a DI-sword. Rimi – also a Gigalomaniac – tries to save her, but is attacked by Norose and taken prisoner in Nanami's stead. Shogun again meets with Takumi to tell him that he had intended to stop Nozomi from taking over humanity with Noah II, but that his body – aged from disease and overuse of Gigalomaniac powers – hindered him, prompting him to create Takumi to do it in his stead. Takumi obtains a DI-sword, and destroys the transmitters, revealing the nurse Hazuki to be the New Gen killer in the process by reading her memories and projecting them onto the screens on the buildings. An earthquake occurs, destroying much of Shibuya; Takumi rescues the other Gigalomaniacs from the destruction, and continues to the location of Noah II. He fights Norose, but Noah II overwhelms him with delusions; he reaffirms his existence with the help of the other Gigalomaniacs' delusion synchronization, and destroys Norose and Noah II with his DI-sword. Lying in the ruins of Shibuya, depending on what the player chooses during the synchronization, he either gives up his life along with the dying Shogun's (in the "A" route), or stays alive with Rimi (the "AA" route). In Chaos;Head Noah, players are locked onto the "Silent Sky" route the first time they play the game – similar to the original's "A" route – and it also features additional routes dedicated to the female main cast.

Development and releaseEdit

Chaos;Head was developed in a collaboration between 5pb. and Nitroplus,[3] who describe it as a "delusional science novel" (妄想科学NVL, Mōsō Kagaku NVL).[4] It was planned by Chiyomaru Shikura,[5] the founder and executive director of 5pb.,[3] and was written by Naotaka Hayashi, with character designs by Mutsumi Sasaki and concept art by Yukihiro Matsuo.[6] Shikura intended to make the story based on reality to make it more relatable, saying that he personally finds it difficult to get excited for fantasy stories.[3]

The game's music was composed by Takeshi Abo, Toshimichi Isoe, Yoh Oyama, and Shintaro Jimbo, with Abo composing 21 of the songs. While it was common for games in the genre to have music that is played in several scenes, Abo had to compose several songs that specifically matched certain individual scenes that were intended to be shocking and dark. He described the main image for the game's sound as "rainy", compared to the later Science Adventure games Steins;Gate, Robotics;Notes and Chaos;Child, which he called "cloudy", "clear weather" and "stormy", respectively. In preparation for composing the music, Abo read the game's story to understand the setting and the character personalities as much as possible. He wrote down his first impressions of the game's emotional flow and of the events and situations throughout the story, and used them to create a musical worldview for the game. He said that this approach takes more time than it would to just designate songs to the different areas in the game, but that it made it possible to create better songs with a greater relationship to the game's worldview.[7]

Chaos;Head was originally announced under the title Gigalomaniacs (ギガロマニアックス, Gigaromaniakkusu),[8] and was released for Microsoft Windows on April 25, 2008 by Nitroplus.[4] Around June 2008, the developers decided to port the game to Xbox 360 with added content:[9] this version was released on February 26, 2009 as Chaos;Head Noah.[10][11] Chaos;Head Noah was ported to multiple platforms, including PlayStation Portable on June 24, 2010,[12] iOS on November 18, 2010,[13] Android on January 24, 2012,[14] and PlayStation 3 on November 22, 2012.[15] While the Xbox 360 version was rated Z (18 years and up) by CERO, the PlayStation Portable and PlayStation 3 versions were edited to be able to be released with a D rating (17 years and up). The PlayStation Vita version bundled the Z-rated version with the follow-up game Chaos;Head Love Chu Chu! under the title Chaos;Head Dual, and was released on August 21, 2014.[16] Another bundle, Chaos;Head Noah / Chaos;Child Double Pack – also known as Chaos; Double Pack – collects Noah and Chaos;Child, and was released for the Nintendo Switch on February 24, 2022, with high-definition graphics.[17]

In 2018, Shikura responded to fan requests on Twitter, saying that Chaos;Head Noah "probably" would be released in English,[18] and in February 2022, Mages asked people to wait for information on an English release.[19] An English localization of Chaos; Double Pack by Spike Chunsoft was eventually announced in March 2022, and is planned to be released on October 7, 2022.[20] On the same date a standalone version of Noah will be available on Windows via Steam.[21]


The game was a commercial success, and, together with Steins;Gate, helped establish 5pb. as a game developer.[3] One month before the game's original April 2008 release, Chaos;Head was the fourth most pre-ordered PC game in Japan.[22] It debuted as the third highest-selling PC game of April 2008 in Japan;[23][24] it became the sixteenth highest-selling visual novel game on the video game store during the first half of 2008,[25] and thirty-fifth overall for the year.[26] Chaos;Head Noah was the eleventh best selling video game of the week in Japan during its debut week, with 18,000 copies sold.[27]

Writing for Kotaku, Richard Eisenbeis found Takumi very unlikable, to the point of being unsure whether the player is meant to sympathize with him. He also noted that the game was short compared to the later Science Adventure games, and that the main characters never come together as a group and are not a vital part of Takumi's life, with Takumi instead "wandering in and out of their stories". Despite this, he found the plot and world gripping, and said that the game was not bad, but that it "might as well be nothing" compared to Steins;Gate.[1] Kowachi from Dengeki Online recommended Chaos;Head Dual for having characters rich in personality and a unique protagonist, and praised how Takumi grew as a character throughout the story.[28] Jenni Lada at TechnologyTell recommended the game, calling it an interesting and mature story, and called its lack of an English release unfortunate.[29] Game Informer included Chaos;Head on a list of games they wanted to see localized; they considered an English version likely due to Steins;Gate's English release in 2014.[30]

Related mediaEdit

Chaos;Head has seen several adaptations and tie-in media. The internet radio show Chaos;Head Radio Delusional Radio Channel[a] began airing on March 28, 2008, to help promote the game and was hosted by Takumi and Rimi's voice actors, Yoshino Hiroyuki and Kitamura Eri.[31] A manga adaptation by Sumihey started serialization in ASCII Media Works' shōnen magazine Dengeki Daioh on May 21, 2008.[32] A second manga, Sakaki Nagako's Chaos;Head: Blue Complex, began serialization in Media Factory's seinen magazine Monthly Comic Alive on September 27, 2008.[33][34] A third adaptation, Mizuki Takehito's Chaos;Head H,[b], was serialized by Jive in Comic Rush beginning on September 26, 2008.[35] An anime adaptation by Madhouse Studios aired in 2008,[36] and was released in English by Funimation.[37][38]

Two video games based on Chaos;Head have been made: the romantic comedy Chaos;Head Love Chu Chu![39] and the thematic sequel Chaos;Child.[40] Additionally, Shikura has said that he wants to create an erotic video game based on Chaos;Head and Chaos;Child, targeting adults.[5] The Chaos;Child anime adaptation also includes an adaptation of Chaos;Head as part of its "episode 0" recap.[41]


  1. ^ Chaos;Head Radio Delusional Radio Channel (Chaos;Head ラジオ 妄想電波局, Chaos;Head Rajio Mōsō Denpakyoku)
  2. ^ Chaos;Head H (かおすへっどH, Kaosu Heddo H)


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External linksEdit