Alter globe size...
	Alter globe speed and directio...
	Bonus lives...
	Debug mode...
	Level skip...
	Switch day and night...
	Unlimited weapons, energy, and...
	Vector graphics mode...

Press Up or Down at the mission selection screen.

Hold 4 + 6 at the mission selection screen.

Hold 3 + 6 + 9 + # at the mission selection screen. A sound will confirm correct code entry. Up to nine extra lives may be selected.

Press Up + A + B + C + 6 during game play. The top right number indicates the current frame rate.

Hold 2 + 4 + 6 + 7 + 8 + 9 at the mission selection screen. A sound will confirm correct code entry.

Hold Up + A + B + C + 7 during game play.

Hold Down + 3 + 4 + 6 + 7 at the mission selection screen. A sound will confirm correct code entry.

Hold Up + A + B + C + 3 during game play.