Golden Axe: Level select:
Select arcade mode. Hold Down/Left + B and press Start at the character selection screen. A number that corresponds to the starting level will appear in the upper left corner of the screen. Use the D-pad to change this value.

Golden Axe: Nine continues:
Select arcade mode. Hold Down/Left + A + R. Release the buttons and press Start.

Sonic Spinball: Multi-ball stage:
Collect all the rings on a level and use the gate that appears to be a large shining ring.

Ecco The Dolphin: Cheat mode:
Turn Ecco to the left or right. Pause game play when Ecco is facing the screen. Press Right, B, R, B, R, Down, R, Up. A cheat menu with stage selection, sound select, and unlimited life will appear.