Galaxian

Destroy waves of attacking Galaxians by moving left and right and firing. The

Galaxians will sit in formation above you, and you can pick them off with

your Cannon. Beware - You can only fire one shot at a time. Your next

bullet will not reappear until your last one has disappeared. Also, the

Galaxians become more and more aggressive as the waves proceed. They

will break formation and swoop down on you as they attack.