Imagine you are on the Earth's orbit watching the Blue planet when many enemy fighters emerge. The fist thing you note is the area that looks almost real. You control a cannon and with it you aim the enemy ships and destroy them. They are mostly very fast and tough to liquidate so shoot quickly. After they explode a small probes stay after them and they must be shot too if you want finish the mission. In the end of each level you have to fight a big boos.