- Adaptation Displacement: More people know about the anime than the game it was based on.
- Complete Monster: Norose Genichi, head of the NOZOMI Group (Noah OrganiZation Of Medical Instruments), is a sneering, arrogant maniac who specializes in the Mind Rape of young girls. Operating as The Chessmaster to get the heroes, superpowered beings called Gigalomaniacs, to do what he wants to further his ends, Norose orchestrates the gruesome New Gen Murders specifically to destroy the protagonist Takumi Nishijou's sense of self and make him break down. He previously experimented on Sena's family, using her mother as a test subject in creating matter from artificial delusions. He forced a woman who had lost her baby to have a new one from her delusions until he decided he'd gotten enough information and ended the experiment, causing the woman to lose her mind and stab her eyes out, which Norose found quite amusing. He later has both Takumi's sister Nanami and Rimi kidnapped to lure out Takumi. His ultimate goal is to extract Takumi's DNA and use it to power Noah II, which he will use to control all humanity. Finally, he causes a destructive earthquake with the device before betraying and killing his two co-conspirators so he can rule by himself. While Norose claims he has good intentions, he is nothing more than a petty tyrant with a god complex seeking to enact his designs on a world he sees as having no point by hurting those in his way.
- Idiot Plot: Most of the plot consists of Takumi trying to get away from everyone who could help him due to his paranoia.
- Jerkass Woobie: Takumi isn't made out to be the most appealing protagonist; he's an antisocial, cowardly otaku who at first is really only concerned about maintaining his lifestyle. At the same time he's put through a fair amount of trials, accused of murder, and pretty much thrust into plot pretty forcefully. Not to mention finding out he's a delusion.
- Moral Event Horizon: Norose's treatment of Nana when Rimi comes to rescue her. You can only really go downhill from there.
- Paranoia Fuel: The fact that the main character is paranoid, everything is seen from his perspective and he is not real (though one could easily argue that he is both real in some sense and not real in some sense).
- Polished Port: The Noah version for the Xbox 360 and PS3 counts, with new routes and HD resolution.
YMMV / Chaos;Head