A Space Invaders style game.
As in Space Invaders, the aim of this game is protect the planet from an alien invasion by shooting from a fixed base on the bottom of the screen game. The similarities with Space Invaders stop there. In this game you use a sight to control your shots, there are four different types of weapons to choose from (although you have to possess enough ammunition for the different weapons) and all this is done while moving your shooting base horizontally across the bottom of the screen.