Marathon

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 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.

Description
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 A.I.'s 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. Most of the editing tools were made for legacy Mac OS versions, so it is very tedious for PC users to design game mods for Marathon.