he object of the game is to destroy incoming enemy spacecraft, bombs, missiles, and asteroids without destroying friendly vessels. Due to the very quick enemy ships and asteroids, the game is considered to be one of the most challenging NES Zapper games. The shield of the player's spacecraft constantly goes down with each missed shot at an enemy. Players can use a powerful bomb to destroy everything on screen, shoot a comet power-up that grants temporary protection from a limited number of hits, and a shield-repairing item dropped off by a friendly spacecraft. Game bosses are fought at the end of each level as the player moves through the Solar System. When the player reaches the Earth level, the player must battle and destroy the final boss, who is an alien named Nemesis. The goal is to retrieve vials of medicine and deliver them to the Earth while preventing Nemesis from passing through the planet's