Here's a holiday treat: Bungie has just announced that its Marathon series is available free for download on the Mac, Windows, and Linux platforms. And that's not all! They have been polished and remade using the open-source Aleph One 1.0 engine!
Since the release of the Marathon 2 source code, Aleph One development community has worked hard to bring Marathon games to all computer-based platforms. The engine enhances Bungie's original Marathon games with up-to-date "OpenGL shader support, Internet co-op and multiplayer, modern mouse-look and gamepad support and plugin support for modifications."
Each game from the trilogy has been substantially improved. Marathon has been updated with a modern HUD, high-resolution graphics and among extensive changes. Marathon 2: Durandal has been upgraded with the high-resolution graphics, which was previously only available as an Xbox LIVE Arcade game. Marathon Infinity, the final game in the trilogy, has also been updated with high resolution graphics.
One of the trilogy's biggest contributions to the gaming industry was that it gave players the ability use the mouse to look up and down in addition to panning side-to-side; it was the first game to do this. They also taught Bungie the importance of story in a game by featuring computer terminals where players could choose to learn more about the game's world. The first title was released in 1994 and was regarded important part of gaming history as well as a commercial success.
I've never played any of Bungie's games except the Halo series, so I will definitely be checking this out.
All three games can be downloaded here: