Crime Game - Houritsu no Nai Sekai is a Manga/Manhwa/Manhua in (English/Raw) language, GORE series, english chapters have been translated and you can read them here. You are reading chapters on ManhwaZ fastest updating comic site. The Summary is
Amagoe Homura, a high school student you can find anywhere, finds himself in a devastated version of Shibuya. A mysterious figure calling himself "Unknown" tells everyone that they can commit any crime in this world, and forces them to participate in a death game where they compete on who can commit the most severe crime...!