Level Skip
During the game, pause and then hold L1 + L2 for ten seconds. The cursor should turn red and can't move. Continuing holding L1 and L2, press Left, Triangle X, Right, Circle Triangle, Down
Refill Health
During the game, pause and then hold L1 + L2 for ten seconds. The cursor should turn red and can't move. Continuing holding L1 and L2, press Down Right Left, Triangle, Right, Down. Now when game is paused, you should have the option avaible.
Play as Fwank
Go to the character selection screen and highlight Mamma. Then press L1, Circle, R1 Down, Down, R1, Circle, L1, L1
Play as a walking corpse
First enter Health Refill code. After dying and before regenerating, use the health refill. You'll be a corpse, totally invulnerable to all enemies. Your actions are limited so this isn't of much use for it.
Weapon Power-Up
The cursor should turn red and can't move. Continuing holding L1 and L2, press Left, Up, X, Circle. Now when game is paused, you should have the option avaible.