There is a level selecter from the start menu. Press left/right on the D-Pad to select and just start the game.
While pause you can also hold L+R+Select to go back to the title screen. Or press up/down to do different poses.. the src is in the download if you look for hacking resources. It is a one day hack so do not expect too much.
Have Fun exploring the levels you never seen since game over did erase progress in the orginal game.