Films about murder games of various sorts have become a popular Japanese-movie subgenre, beginning with the ultra-violent Kinji Fukasaku hit "Battle Royale" (2000) and continuing with the even more successful "Death Note" trio of films (2006-2008) — though the "game" in the latter was more of a battle of wits between the killer hero and the candy-addicted private detective hired to stop him.
Most of these films are thrillers with a thin overlayer of commentary about the dire state of society. Aiming for a semblance of realism, psychological or social, they usually end up looking contrived, since the "game" is rigged from the beginning to ensure the survival of the leads.
Shinsuke Sato's "Gantz," the first of two films based on a popular manga by Hiroya Oku, stands the "murder game" formula on its head — or rather twists it in ways provocative and strange.