Sound Test
Go to the game's Option Screen. Then scroll down the screen to
reach the Sound Mode. Next, hold L + R + X + A. While holding
these, hold the center of the directional pad, then press Select.
A Music Menu will appear. Select different tunes and enjoy!
Stage Skip
While paused press RIGHT, LEFT, DOWN, RIGHT, A and then press
START again to unpause. This will allow you to skip any stage
in the game.