Level select:
Power on the system, then hold Run and press Select ten times. Enter one of the following codes at the title screen to begin game play at the corresponding level.

Level	Code
2	Up + Select + Run
3	Right + Select + Run
4	Down + Select + Run
5	Left + Select + Run
6	Up + Right + Select + Run

Sound test:
Power on the system, then hold Run and press Select ten times. Then, hold Select and press Run at the title screen.