You have landed on an alien planet, and now the locals are trying to destroy your spaceship! Defeat the alien monsters so you can make your way back home safe and sound. Use the WASD keys to control the turret to directly attack the monsters. Then use the money made from killing the aliens to build more troops to fight the enemies on their own turf. Use the money earned to upgrade both your ship and your units, to have a better defense and offense as you work your way through the lands of evil aliens. Do not rest until you have destroyed them all and can go home safe.