To use these codes, pause the game and enter any of the following. To turn a code off, just re-enter it.

Freeze computer players -- Left, Left, Up, Down, R2
Extra damage -- Up, Up, L1, L2, Down
Enable combos -- R1, L2, R2, L2, Right
Humans take minor damage -- Down, Up, L2, Right, Left
Automatic super-pins -- Down, Down, Down, Down, Lw