If you put the game disc into a computer, find the file named "Omake." It's a game poster for your desktop.
Secret Characters
Play as Karbankle or Dopple Aruru in either Free play against the CPU or 2 player vs. To do this you must beat the story mode, after the credits roll skip the ranking screen (it will automatically save your score now) then go to either free play or vs mode. Hold the left or right trigger then push Y. You will find the characters to the left of Satan or right of Schezo. Hold the Left Trigger for Dopple Aruru and the Right Trigger for Karbankle. You can save this to the VMS so they will be ther every time.
Play as Dopey
Successfully complete Quest mode. Pause at the ranking screen. Hold L next to Satan and get "Dopey".