Invincibility:
Hold Option 2 + Option 1 (in order), and press Up/Right at the title
screen after the Slime World logo falls. Release all buttons and
begin game play. REMEMBER: The game may crash in multiplayer mode when
this code is enabled.

Zit popping mini-game:
Enter the screen with the green Todd that appears after the summary
screens. Press Option 1 to display a zit and pop it by quickly
hitting the other buttons. This game may be played in multiplayer
mode.