Halo Zero

Halo Zero takes the famous sci-fi universe and squeezes it into a fast-paced 2D action game, because apparently Master Chief was not busy enough saving the galaxy in three dimensions. Players run, jump and blast their way through side-scrolling levels packed with enemies, weapons and the familiar Halo atmosphere. The project is unofficial, but it clearly understands the appeal of the source material, translating its military science-fiction action into a more compact arcade-style format. It is especially interesting as a fan-made snapshot of the Halo community during the 2000s, when ambitious freeware projects regularly attempted things that would have seemed completely unreasonable a few years earlier. Sometimes they even worked.