Level skip
Press [Left], [Up], [Left], [Up], [Start], [B], [Right] at the beginning of a level to jump to the next level. Press [A] at the beginning of a level that has already been completed to return to the previous level.
Item select
Enable the "Level skip" code and begin game play at the desired level. Then, press [Start] and press [A] to get the shoes; press [Start] and press [B] to get slime; press [Start] and press [C] to get a sword, eyeballs, or bubbles.