Level select
Hold [L] + [R] and press [Left]x2, [Right], [Down]x2, [Up], [Right] at the "Press Start" screen. A blubbering sound will confirm correct code entry.
All characters' jet packs
Hold [L] + [R] and press [Left], [Up], [Right], [Down], [Left]x2, [Up] at the "Press Start" screen. A blubbering sound will confirm correct code entry.
All items
Hold [L] + [R] and press [Left]x2, [Down], [Right]x2, [Up], [Left] at the "Press Start" screen. A blubbering sound will confirm correct code entry.
Everyone invincible
Hold [L] + [R] and press [Left], [Down]x2, [Right]x2, [Left], [Down] at the "Press Start" screen. A blubbering sound will confirm correct code entry.