Invincibility
Pause, Square, Square, Circle, Circle, Triangle, X, Square, Up, Up, Down, Down, L1, R1, Select.
Level Skip
Pause, Square, Circle, Triangle, Right, Left, Down, R1, L2, R2, L1.
View ending sequence
Pause the game and press Square, Circle, Triangle, Right, Left, Down, R1, L2, R2, R1.