right and left arrow key (← →) to rotate your gun up arrow, space bar, or click to shoot Prevent enemy paratroopers from landing on either side of your gun by shooting them or taking down their helicopter. If four paratroopers land on one side of your base they will overpower your defences and blow up your gun. Shooting down an enemy helicopter will earn you 10 points, and shooting down an enemy paratrooper will earn you 5 points. Each bullet you shoot will cost you 1 point.