Iron Sky: Invasion is a space action simulation based upon the movie Iron Sky. In the year 1945 a Nazi force fled to the dark side of the moon and plan their comeback to establish the fourth Reich. In the year 2018 the invasion of the Earth started. Giant carriers bring swarms of Reichflugsscheiben to the Earth. Only a small force of armed space vessel are ready to defend yourselves.

The player has the control of a space fighter and hunts down the Nazi ships. Destroyed ships may drop scrap metal, which can be collected and is used to buy upgrades for the different fighters. Beside the story missions there are detectable side missions which will provide additional scrap metal. All battles took place in the space, there is no gravitation and no surface. The only objects the player may collide are other space ships.

The game contains a lot of characters like Mrs. President or the Mondführer as well as the ships from the movie like the Götterdämmerung or the Mars exploration spacecraft USS George W. Bush.