Invincibility
Pause the game, hold L2 or R2 and press Right, Right, Left, Triangle, X, Up, Circle, Left.
Infinite Spirit Spells
Pause the game, hold L2 or R2 and press Left, Triangle, Left, Left, Circle, Left, Triangle, Right, Circle, Up, Up, Down.
Debug mode
Pause the game, hold L2 or R2 and press Left, Up, Up, Triangle, Right, Square, Left, Triangle, Up, Down, Right, Right.