Description: You must defend your fortress from the oncoming enemy waves. Place turrets in locations of your choice on your fortress, creating the best defense possible to withhold even the greatest of attacks. Purchase, Repair, upgrade, and move your turrets to find the ultimate defense. Tutorial is available on the first campaign. Hotkeys can be reconfigured through the settings menu option. Press P key to pause. Game automatically saves after each level so you can easily come back later.