Marathon is a first-person shooter video game developed and published by Bungie, and released in December 1994 for the Apple Macintosh. The game takes place several centuries into the future in outer space and sets the player as a security officer attempting to stop an alien invasion aboard a colony ship named the Marathon.
Marathon is the first game in a series of three games collectively known as the Marathon Trilogy, which also includes its two sequels, Marathon 2: Durandal and Marathon Infinity, released in 1995 and 1996 respectively. In 1996, Bungie released Super Marathon, a port of Marathon and Marathon 2 to the short-lived Apple Bandai Pippin video game console.
Bungie released the source code of Marathon 2 in 1999, which enabled the development of an open-source enhanced version of the Marathon 2 engine called Aleph One. The game's assets were released by Bungie as freeware in 2005.
Gameplay takes place in a real-time, 3D-rendered world of ceilings and floors of various heights and widths, all viewed from a first-person perspective. All surfaces in the game are texture mapped and have dynamic lighting. The player assumes the role of a nameless security officer aboard a large colony ship called the Marathon, constructed from Mars' moon Deimos. The player controls the movement of their character primarily through use of the keyboard. Using assignable keys, they can move forward and backward, turn left or right, sidestep left or right, look up, down or forward, and glance left or right. Marathon also features free look, allowing the player to use the mouse to fire weapons and rotate their character's view. Marathon was one of the earliest computer games to employ free look and give the player the ability to look up or down. The game interface includes an overhead map, a motion sensor indicating the positions and movements of both enemies and allied characters through red triangles and green squares respectively, and bars displaying the player's current shield and oxygen levels.