Kansen 2: Inzai Toshi

Based on the erotic game by Speed. Kansen 2 (like the first episode) takes place during the initial outbreak of the Unknown virus epidemic, but the protagonists here have a much harder lot because they are stuck in the middle of a contaminated city immediately after its destruction by a mysterious cataclysm. Stalked by hordes of infected maniacs, Hiroshi Ookura and his friends seek safety inside a mostly intact shopping mall, but madness and death are everywhere... (Source: Visual Novel Database)