However, Bungie released the source for Marathon 2 in 1999, allowing the development of the open-source multiplatform Aleph One engine that is also compatible with Infinity.

In 2011, Bungie released the source code for Marathon Infinity itself, preceding an official Aleph One-based port for iOS the next year that is available free (with in-app purchases).

[1] The story in the single-player version of Marathon Infinity, titled "Blood Tides of Lh’owon", is not told in an explicit fashion.

At the end of Marathon 2 proper, as the Pfhor's Trih Xeem or "early nova" device is fired upon the S'pht System's sun to explode it, Durandal recounts an ancient S'pht legend in which a chaotic entity known as the W’rkncacnter — an eldritch abomination — was sealed inside of that sun by the Jjaro — a highly advanced race from centuries past, their technology being the only remnants of their existence — eons ago.

The story involves the player "jumping" between alternative realities via surreal dream sequences, seeking to prevent the W’rkncacnter from being released from Lh'owon's dying sun.

One of the most dramatic improvements in the game was the inclusion of Bungie's own level-creating software, Forge, and their physics and in-game graphics editor, Anvil.

Forge and Anvil allowed a new generation of players to create their own levels and scenarios using the same tools as the Bungie developers themselves.

Allgame editor Alexander Goldman described Marathon Infinity as "the standard against which other Macintosh shooters are compared".

[2] The editors of CNET Gamecenter named Marathon Infinity the best Macintosh game of 1996 and wrote that its "design and playability [...] pushed it into the stratosphere".