Commander Keen 2 online DOS game The Earth explodes is the first of a series of single-player side-scrolling platform video games. The series follows the eponymous Commander Keen, the secret identity of the eight-year-old genius Billy Blaze, as he defends the Earth and the galaxy from alien threats. This sequel’s gameplay is pretty similar to the first one, as the main character has to go through different levels and defeat the evil Vorticons, his enemies, who in this version of the game are much more fearful. Also, the gameplay is slightly different, with some moving platforms and buttons that makes the game more difficult and interesting to play. The goal will be to deactivate all the cannons, put by the aliens, to save the world.