The player controls a lone spacecraft on a mission to singlehandedly take down the entire enemy armada. Enemy fighters and ships shoot at the player, and there are mines and other objects that must be shot or avoided. The game is divided into waves. At the end of each wave is a command ship that must be destroyed. In later waves the enemy fighters move and shoot more aggressively, and their shots are more accurate. Some waves take place in open space, while others require the player to battle enemies while flying through narrow trenches and tunnels. The player is on a timer at the beginning of the game, with an unlimited number of lives available. The length of the timer can be adjusted by the machine operator, but is normally 60 seconds. After the timer expires, the player is given a limited number of additional lives. When all of those lives are lost, the game ends. Less