General information

What is Aleph One/SDL?

Aleph One is an Open Source 3D first-person shooter game, based on the game Marathon 2 by Bungie Software. It supports, but doesn't require, OpenGL for rendering. Aleph One was originally a Mac-only game, but there is now a cross-platform version based on the Simple DirectMedia Layer (SDL) library, that should in theory run on all systems supported by SDL (Linux, BeOS, Windows, Mac OS, Solaris, IRIX, *BSD, and others). Except for a few minor things, the port is complete and playable.


Level Selection Dialog In The Line Of Fire [Marathon 2] Lava Pool [EVIL] Power Generator [Siege of Nor'Korh]
Mission Objectives [Marathon 2] Air Pfhor in Waterloo Steambath [Marathon 2] When The Dust Settles... [EVIL] Assortment Of Panels [Chai'etra Saga]

Download Aleph One/SDL

Current version

Current versions of Aleph One can be downloaded from

The source code is available on GitHub:

Obsolete builds

See below for installation instructions.

Aleph One data files

These are freely distributable but not Open Source. See here for details.

Marathon scenario files

The original Marathon 1 data files are not compatible with Aleph One, but Raul Bonilla and the M1A1 team have made an excellent conversion called M1A1:

Marathon 2 scenario files

Marathon Infinity scenario files


Required libraries

Installing And Playing Aleph One/SDL

The installation of Aleph One/SDL consists of two steps:

  1. Installing the Aleph One/SDL program
  2. Installing Marathon data files

1. Installing the program

From a binary package

Compiling from source

  1. You will need to have the SDL library installed. Aleph One requires at least SDL 1.2.0. Note that if you didn't install SDL from source, you will also have to install the SDL-devel package.
  2. Download the Aleph One/SDL source tarball, or get the source from GitHub.
  3. Under Unix, install Aleph One as follows:
    $ ./configure
    $ make
    [become root]
    # make install
    Under BeOS, do this instead:
    $ make -f Makefile.BeOS install
    This will compile the source and create a directory AlephOne in your home directory that contains the AlephOne application and some data files.

2. Installing the data files

To play Aleph One, you will also need Marathon scenario (graphics, sound and map) data files. For your convenience, I've created archives containing the data files from the now freely available Marathon (M1A1), Marathon 2 and Marathon Infinity scenarios, converted to the formats needed by the SDL version of Aleph One.

The packages contain the files Images, Map, Map.resources, Music, Shapes, Sounds, some scripts, and the respective instruction manual in PDF format (from the original Mac version).

Playing Aleph One

First, be sure to read the README file that comes with Aleph One/SDL.

How you can help

If you are serious about developing for Aleph One, you should subscribe to the marathon-devel mailing list. If you have only small patches for the SDL version, you can send them directly to me.

But wait, there's more! Up to now, Marathon has mostly been a Mac-only thing, and nearly all the scenarios, tools, graphics etc. made by the Marathon community only run on Mac OS. This is where you come in. We need cross-platform

If you're interested in or already working on one of the above items, feel free to contact me and I will add a link to your project's page.

Bug reports and feature requests

Bug reports and feature requests can be submitted via the bug tracker on GitHub.

Frequently Asked Questions (FAQ)

What is Aleph One?

Aleph One is the Open Source version of Marathon 2.

What is Marathon?

Marathon is a three-part game series published by Bungie Software, consisting of Marathon, Marathon 2, and Marathon Infinity. They are first-person shooter puzzle games with Doom-like graphics, set in a scifi universe dominated by deviant computer AIs and (unlike Doom or Quake) a well thought out plot. The original Marathon game was released in December 1994. With the exception of Marathon 2, which was also available for Windows 95, all Marathon games have only been released for Mac OS.

Open Source?

On January 17, 2000, Bungie Software released the source code of the Mac OS version of Marathon 2 under the terms of the GNU General Public License. Since then the game has been enhanced and extended, under the name of "Aleph One", by a team of developers on the Internet. Two of the biggest improvements to the game so far are the addition of OpenGL rendering and a built-in scripting language.

What is "Aleph One/SDL"?

Aleph One was originally a Mac-only project. Later, a cross-platform version based on the SDL library has been developed. This version runs on Linux, *BSD, Windows, Mac OS X, BeOS, and eventually other systems supported by SDL.

What is SDL?

The Simple DirectMedia Layer (SDL) library is a cross-platform multimedia library designed to provide easy and consistant access to graphics, sound, and user input, under a large number of operating systems. It is used by many popular games, most notably by most of the games published by Loki Entertainment.

Wasn't Bungie acquired by Microsoft?

Yes, but this doesn't affect the development of Aleph One.