Chaos;Head (stylized as "ChäoS;HEAd") is a visual novel video game developed by 5pb. and Nitroplus. It is the first entry in the Science Adventure series, and was originally released for Microsoft Windows in 2008; an enhanced version titled Chaos;Head Noah was released for Xbox 360 in 2009, and has since been ported to multiple platforms. The game follows Takumi Nishijo, who gets caught up in the "New Gen" serial murders. He frequently experiences delusions and hallucinations; the player can use the "delusional trigger" system to decide whether he should experience positive or negative delusions, which determines the story's ending.