Grobda: Level select:
Hold L1 + L2 + R1 + R2 and press Start at the Grobda title screen. Choose a level from the battle selection screen.

Mappy: Level skip:
Load the game and press Triangle to display the dip switch screen. Enable switch 5 in box SW3 by pressing X while it is highlighted. Begin game play. Press L1 + R1 + X to jump to the next level.

Extra credit:
Press Select while playing any game.

Dragon Buster: Increase vitality:
Press Select(10) and start the game at the Dragon Buster title screen. Press L1 + R1 when your vitality drops below 33 to raise it 128 at the cost of one credit.

Dragon Buster: Level skip:
Load the game and press Triangle to display the dip switch screen. Enable switch 5 in box SW2 by pressing X while it is highlighted. Begin game play. Hold L1 + R1 + Circle and press Start at the map screen. Release the buttons when the desired level appears.

Gaplus: Level select:
Load the game and press Triangle to display the dip switch screen. Enable switch 4 in box SW3 by pressing X while it is highlighted. Begin game play. Hold L1 + R1 + Circle and press Start when the phrase "Parsec 1" appears. A number corresponding to the current level will appear on the left edge of the screen. Press Up or Down to adjust this number and press Start to begin at the displayed level.