Sound test:
Wait until the first beep is heard at the continue screen. Hold Up
+ Option 1 while "9" appears on the countdown timer. Continue to
hold the buttons at the "Game Over" and demonstration screens.
Alternatively, hold Option + Up before the title screen appears. A
demonstration mode with cycling colors and a new song will start.
Use the D-pad to play game sounds. Repeatedly tap Down + Left to
lower the pitch of the sound. Repeatedly tap Up + Right to raise
the pitch of the sound.

View development team:
Hold Up + Option 1 when the screen fades to black before the
continue screen. Continue to hold the buttons through the countdown
sequence. A white dot will appear in the center of the screen after
the countdown. Rapidly tap A, B repeatedly (or sweep the D-pad) to
magnify the dot to a picture of the development team.