In the near future the human race has found a way to travel among the stars. In their journeys through space they have found a habitable planet similar to earth. Just as they have started to settle on this planet, that was believed to be peaceful, huge monsters have come to destroy the base. Luckily your scientists have developed turrets to beat the monsters back. Place your turrets along the path to the base to keep them from reaching it. Match the kind of monsters with the kind of turret in order to cause the most damage. Don't stop till you have wiped out all the monsters and made the planet safe to live.