From site: Planet Earth is threatened by evil space invaders. You have to keep them off from landing and occupying the planet. You will succeed by pressing the according key to the space ship. However, you only can eliminate the leading ship! During the battle, new space ships will appear constantly...
The game consists of 40 attacks. Eight levels, where the program queries certain keys more than in the level before, and five sub-levels, where beginning speed increases. One level is won if all space ships are eliminated. Planet Earth is saved if all 40 attacks are won. If a space ship has landed on the planet, the game is lost. You also can repeat single levels.
