In Commander Keen in Invasion of the Vorticons, Keen must travel to the Vorticon mothership to deactivate the X-14 Tantalus Ray cannons that are locked onto eight of Earth's landmarks. He must fight enemies and hazards, and a Vorticon at each cannon's control, to do so. Keen eventually discovers that the Vorticons are being mind-controlled by the Grand Intellect, who is the mastermind behind the attack on Earth.