Multiple Bonus
When you begin a new game, quickly find a place safe from enemy attacks, then press X, A, B, Y, A, B, Y, X, B, Y, X, A, Y, X, A, B on Controller 2. If the code is entered correctly, you should hear a tone. After you have entered the code, you can use Controller 2 to access the following power-ups:

L Button - Level Skip
Left - Nine Keys
Up - Nine Lives
Down - Nine Bombs
Right - Reset Timer