Publisher statement You have to be quick to shoot these invaders as they zig and zag down from the top of the screen. You can move your gun laterally with the joystick and fire with the button from your supply of 75 rounds. You score points for each attacker you hit, and lose a player ["life"] if the attacker hits you. At the end of each wave your score is enhanced by the number of players you have left. User summary Game program by Mike Colvin with the assistance of Jerry White.