Aleph One is the open source continuation of Bungie's Marathon 2 game engine. Available for Mac OS X, Windows, and Linux, Aleph One supports Marathon 2 and Marathon Infinity natively, and Marathon through a fan-made conversion. Many third party scenarios and net maps are also available. Aleph One is available under the terms of the GNU General Public License (GPL) and the final stable version 1.0 build for Alpeh One has been released recently.
Marathon is a first-person shooter video game with a science fiction theme, developed and published by Bungie and was released in December 1994 for the Apple Macintosh. Marathon features action-heavy, first-person shooter gameplay similar to Doom. The game is renowned for having an intricate story line which is an essential element of its gameplay whereas most similar games devote minimal attention to plot for the sake of faster, simpler, more action-oriented gameplay.
Marathon is a fight for survival against the Pfhor, an alien race attacking your colony ship. In Marathon 2: Durandal, you and other survivors hunt for an ancient ally to topple the Pfhor empire. Marathon Infinity forces you to rewrite history to prevent the destruction of the universe. Aleph One comes with high resolution graphics for Marathon 2 and Marathon Infinity.
Get all three games for Linux from here.