Master Cheat:
Goto the Main Menu and enter the following:
Right, Right, Left, Left, Right, Left, Right
This will unlock numerous cheat functions

Play with Titan Difficulty:
Enter the master cheat above and then enter the following:
C-Up, C-Down, C-Up, C-Down.

Gabrielle(as opponent):
Enter the master cheat above and then enter the following:
C-Left, C-Left, C-Left, C-Left

Unlock Bunny Despair:
Enter the master cheat above and then enter the following:
C-Left, C-Up, C-Right, C-Down