Marathon 2: Durandal is the second part of a trilogy of first person shooter games. The game takes place in 2811, seventeen years after the events of the first game. An artificial intelligence called Durandal sends a super human cyborg security officer aboard a captured Pfhor spacecraft out on a mission to search the ruins of Lh'owon, the S'pht home-world.
The sourcecode to Marathon 2 was released by Bungie in 1999. The sourcecode was adapted into an open source project called AlephOne. In early 2004, Bungie released the entire Marathon Trilogy as freeware, allowing it to be downloaded free of charge.
DCEvolution released a Dreamcast image that contains all three games in the Marathon trilogy. This image can be used with any program which recognizes DiscJuggler images to create a CD-R of the game which boots on the Dreamcast. The Dreamcast port of AlephOne requires a Dreamcast keyboard.