Eternal is a free scenario for Aleph One the multi-platform, open-source, first-person-shooter engine derived from Bungie's Marathon engine. It continues the story of the Marathon trilogy, and is a nearly total conversion, featuring:
- Fifty-two new levels, some revisiting familiar locations from the original Marathon trilogy.
- Over six hundred fifty new high-resolution textures, including a dozen original landscape textures, from a variety of human and alien environments.
- Eight all new weapons, many of which must be scavenged from your defeated enemies.
- Over a dozen tracks of original music, including many remixes of your favorite tracks from the original Marathon.
- And several new creatures and characters, alongside the complete cast from the original trilogy.
The third point of the installation instruction given on the site is the other way round on Linux: you need to copy the contents of the Eternal folder into the AlephOne folder, usually /usr/local/share/AlephOne. A more detailed description.