Overwhelmed by enemies? During gameplay, hold down the B button for 6 seconds and you will summon lightning that destroys all the enemies. However, using this costs you a little of your energy.
Select the number of players, then press A, A, A, A, B, B, B, B, A, B, A, B, A, B, A, B. If you entered the code correctly, you'll hear a tone. Now hold down the following buttons on each controller and press Start on Controller 1 to start on that stage or to enter the sound test: