In a world that is being attacked by robots you must reign supreme. Right now you are in charge but the attacking force wants to change that. Use your towers to defeat the attacking robots in order to protect your base and remain ruler. Use your mouse to place the towers and fight back the robots, instead of having a set number of lives, every time a robot completes the circuit you lose a tower. When all of your towers are gone then your nation loses its hold over the land and then the robots win.