Level Select:
At the "Press Start" screen, enter L1, R1, L2, R2, Triangle, X, Circle,
Square, Square, Circle, X, Triangle. Go to the main menu screen to
select any level in the game.
All Ships, Weapons, and Upgrades:
At the "Press Start" screen, enter L1, R1, L2, R2, Up, Down, Right,
Left, Left, Right, Down, Up.
