In a recent interview, David Corless from Sega explained they are working closely with the ratings boards to ensure MadWorld gets a timely release.
"Yes, it is violent. We don't try to hide that, but as publishers we see it as a fantasy game - it's fantasy violence, over the top, cartoony. We're working with the age rating boards, with PEGI and with BBFC. We're not yet at the end of the game's development, but we're talking to them now to make sure that we don't go over the top".
Probably a good idea, since no one wants another Manhunt 2 saga. MadWorld has been garnering quite a lot of negative attention though and is already banned in Germany.
Ultraviolent MadWorld
Dawn of Fantasy Screenshots