Marathon Infinity (1996) Free & legal
1996 · Bungie Software · System 7 · Basilisk II (Mac IIfx) · 640×480 at 8-bit colour
Guide updated September 2026 · needs your own copy
Marathon Infinity is the one where the story stops behaving. You die, and wake up somewhere earlier. You change sides. Whole chapters turn out to be something other than what they appeared. It is a 1996 first-person shooter structured like a short story that folds back on itself, and it should not work as well as it does.
It also shipped with Forge and Anvil — the level and resource editors — which is why the Marathon community outlived the games by decades.
Controls
| Arrow keys | Move and turn |
| Space | Fire |
| Tab | Switch weapon |
| Shift | Run |
| Z / X | Sidestep |
| Delete | Action |
| M | Map |
Released for free redistribution by Bungie in 2005 with the rest of the Marathon trilogy.
Get the trilogy
- Aleph One — all three games, free, with the community's scenarios.
How it works & what to expect
| Machine | Macintosh IIfx, 32 MB RAM, 640×480 at 256 colours |
|---|---|
| System | System 7.5.3 |
| Emulator | Basilisk II, compiled to WebAssembly |
| Speed | Comparable to Marathon 2 — a desktop game here |
The branching that is not branching
Infinity presents itself as a story with alternative paths, and the trick is that your choices are not what move you between them — dying is. Fail in particular ways and the game does not simply reload; it continues somewhere else, in a different version of events, sometimes on a different side of the war.
Because of that, the level list is not the story order, and two people who finish Infinity will describe different games. In 1996 this was genuinely novel and there was no walkthrough to spoil it.
It is also the hardest of the three by some distance. If you want the trilogy's best-paced game, that is Marathon 2. Infinity is the one to play afterwards, when you want it to be strange.
Forge, Anvil, and why Marathon never died
Bungie shipped Infinity with its own tools: Forge for building levels and Anvil for editing the sprites, sounds and physics. Nothing else in 1996 handed you the editors the developers had used, and the result was a modding community that produced hundreds of complete total conversions — some of them, like the Eternal and Rubicon projects, larger than the games they were built on.
That community is why all three games still run on modern machines through the Aleph One engine, which grew out of the Marathon 2 source Bungie released in 2000.
Questions people ask
Should I play this before Marathon 2?
No. Infinity assumes familiarity with the trilogy's world and is the hardest of the three. Marathon 2 is the best entry point.
Is it free?
Yes, along with the rest of the trilogy, since 2005.
What are Forge and Anvil?
The level editor and the resource editor Bungie used to make the game, shipped with it. They are the reason the Marathon modding community exists.
Does the story really branch?
Yes, though not through dialogue choices. Failing in particular ways moves you to a different thread rather than restarting you.
Can I play community total conversions here?
Not directly. Aleph One is the right tool for that — it is linked below.
Is this the last Marathon?
The last of the original trilogy. Bungie returned to the name much later with a separate project.