For the most part, the violence the games have is portrayed in an extremely cartoony way. The violence in the actual gameplay isn't anything you won't see in any sidescrolling game. (Even the KIRBY games had some enemies leave behind corpses after they were defeated) The cutscene violence is pretty cartoonish as well. Jazz detonating TNT in a turtle's shell and Devan getting crushed by a giant piece of rock is pretty much the extent of it, and it's really nothing that you won't find in Looney Tunes and such.