Unlimited weapons, energy, and shields:
Hold Down + 3 + 4 + 6 + 7 at the mission selection screen. A sound will confirm correct code entry.

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

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

Switch day and night:
Hold Up + A + B + C + 7 during game play.

Alter globe speed and direction:
Hold 4 + 6 at the mission selection screen.

Alter globe size:
Press Up or Down at the mission selection screen.

Vector graphics mode:
Hold Up + A + B + C + 3 during game play.

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

Bonus missions:
Enter one of the following codes at the mission selection screen to enable the corresponding bonus mission.

Level 1
Hold Up + 2 + 3 + 6.

Level 2
Hold Down + 2 + 6 + 7 + 8.

Level 3
Hold Right + 3 + 5 + 6.

Level 4
Hold Up + 2 + 5 + 8.

Level 5
Hold Right + 2 + 4 + 5 + 6.