While at the Character Select screen hold A, B, or C and hit Start. Your color will vary based on which button you held.
Cheat Menu
To access the hidden cheat menu, push the d-pad LEFT [three times], RIGHT [twice], LEFT [twice], RIGHT [three times], LEFT, RIGHT at the main menu.
Extra Options
At the main menu press Left, Up, Right, Right, Up, Left, Right, Right, Left, Left, Up. An "Extra Options" menu will appear. From here you can set several options, turn off the timer, or even go bowling!
Fight As Rage
To fight as Rage, hold X, Y and Z at the character selection screen.
Note: This code requires a 6-button controller.
Hopping Devil
Enter the extra-options code at the Start, Options screen. Select *Okay, Right* choose Diablo and when the game starts, Diablo has no followers behind him, but a giant devil bounces around behind him.
No Cheese
When playing as Diablo, back your enemy into a corner, then use his teleport move(Infeno flash) and a no cheese sign will flash at the top of the screen.