Load the game and wait until the high score screen appears. Type commander and press Fire. Wait approximately two seconds and press [F10] to enable cheat mode. Your ship will flicker to confirm correct code entry. During cheat mode, your ship will be invincible, and have unlimited expansions and smart bombs. Additionally, one of the following keys may be pressed to activate the corresponding cheat function. Note: High score will not be recorded while cheat mode is enabled.

Key - Effect

[F1] + [F5] - Other six levels of expansion
[F8] - Level skip
[F10] - Toggle cheat mode