It's kind of strange when you think about it. Here we have Marathon, a very old game getting DLC thanks to the magic of Xbox Live Arcade. 360Sync got a look at the new DLC (complete with new achievements) including some super spiffy videos. The first video, embedded above, shows off the map Duality (originally from the Marathon series and remade as Gemini in Halo 2). Fun fact: Duality was named for a game being created by Double Aught, a company comprised of former Bungie employees. Duality the game, sadly, was never released. The second video (embedded after the break) showcases "Thick and Chunky." The primary feature of the level is the large lava pit in the center, which also happens to be where the hill is located in King of the Hill mode. Ouch.
We're not sure how many more maps could wind up in the upcoming DLC. Keep your eyes on X3F for the latest on what to expect and details on when the DLC will be available.