Cosmic Jailbreak is a shoot 'em up game, with a twist. Like Space Invaders the player controls a tank at the bottom of the screen, has some bunkers to hide behind and must shoot aliens from the playing field. The primary difference is that this time the aliens are not so much invading, as trying to rescue their criminal friends who are locked up in a prison at the center of the screen.

The aliens will move from the side of the screen towards the prison. Each alien that reaches this prison will remove one brick. Once enough bricks are removed the prisoners will escape and it's game over.