According to Bart, it's rated, "Bad for everyone" and requires at least two players to play, as seen when he and Stacey Swanson were playing this game together. On the first level, you destroy all human life forms. 
Bart had one of his sessions with a qualified psychiatrist named Stacey Swanson, whom Bart develops a close bond with. In order to convince Bart to open up about his feelings, Dr. Swanson uses the video game Death Kill City II: Death Kill Stories to persuade him.
Behind the Laughter
Death Kill City II: Death Kill Stories is a parody of Rockstar's Grand Theft Auto video game series, specifically Grand Theft Auto: Liberty City Stories and Grand Theft Auto: Vice City Stories, as it has "Stories" at the end, and the cover is similar to that of the GTA series.