Marathon is a first-person shooter developed for the Apple Macintosh by Bungie. It was released on December 21, 1994. It is often called a Doom clone, however, it is based on Pathways into Darkness, which came out shortly before Doom. Because of Doom's success, Marathon was not as popular as later games such as Duke Nukem 3D, but still had a niche fan base as Doom would not be released for Macs until 1995. All three games in the Marathon series are currently available as freeware for Windows, Linux, and Mac OS X via AlephOne, an enhanced source port. It is notable for being one, if not the first plot driven video game. Most of the time in the game is spent reading terminals, which, although reading has come back in more recent games, was more abundant in this game. It was also the first First Person Shooter to have game modes such as Capture the Flag and Oddball (Called Kill the Man with the Ball in the actual game). another first is set was to include vertical aiming and idle animations for enemies, along with allied computer-controlled units.
In the first Marathon game, the player assumes the role of a cybernetic security guard who stumbles upon the UESC Marathon, a massive starship colony built out of the Deimos moon. Instead of demons from Hell, the player fights off hordes of vicious aliens, while defending panicking crew members and dealing with the ship's AIs via text terminals.
Similar to Doom, the player's starting weapons are a pistol and his fists, and the player faces hazards such as crushing ceilings and lava. The game environment has a similar "2.5D" appearance, with floor, wall, and ceiling textures, actor sprites with eight rotations, elevator lifts, and switches. Notable features included seamless sector-over-sector design, an on-screen motion tracker, free look, swimming through liquids, usage of oxygen tanks in cold vacuum or underwater, and weapons with actual magazines rather than drawing straight from ammo reserves.