Sonic's Secrets: Crue Ball.

Choose 'Music Demo' from the title menu and select Track #6 (Twisted Flipper).

Now press A, C, A, B and begin a new game.

Before you launch the ball, press:

B + Up (Toghether) to advance a level,

or B + Down (Toghether) to backup a level.

First enable the Skip Level code above.

You'll be able to enter a full sound test at any time during the game by pressing:

A + B + C (Toghether).