From the publisher's website:

Are you ready to conquer the earth? Martian Fluxx is a classic monster story in ever-changing card game form. It's an Invasion from the Planet Mars! The players are the Martians determined to destroy the Pathetic Humans who are keeping them from winning. It's got Flying Saucers, Giant Tripod War Machines, Tentacles, Ray Guns, a Mothership, and of course, a Space Modulator. Be careful - you don't want your Humans escaping from the Abduction Chamber! It all begins with one basic rule: Draw one card, Play one card. You start with a hand of three cards... add the card you drew to your hand, and then choose one card to play, following the directions written on your chosen card. As cards are drawn and played from the deck, the rules of the game change from how many cards are drawn, played or even how many cards you can hold at the end of your turn.