the "liberator" controls consist of a trackball, fire button, and shield button. the player controls a coordinated attack from four star ships at the corners of the screen. the primary target of the attack are enemy bases on a rotating planet in the center of the screen. the trackball is used to move a cross-shaped cursor. the fire button fires a missile at the cursor's location from the closest ship. the shield button is used to activate force fields around the ships. the shield can only take four hits each round, and the count is shared between all ships.