Defend against wave after wave of ceaseless UFOs intent on destroying the moon! As they get steadily stronger, you must constantly upgrade your guns to keep pace.Timing is everything – shoot them just before they land to earn maximum rewards. Shoot long sequences of the same colour UFOs to build high-earning combos.The pressure mounts as the flying saucers get faster and faster; combos get harder to make as they attack with more and more colours.Can you handle the frenzy of targeting three guns simultaneously? Or will the moon ultimately fall to the alien threat?