Bungie's pre-Halo FPS Classic Marathon Infinity just launched on Steam for free, meaning you can now play the entire Marathon trilogy for the low price of nothing

Old timey FPS Classic Marathon Infinity has just landed on Steam, meaning you can now play all three Classic Marathon games via Valve's distribution service for free.

Originally released in 1996 (without the word 'Classic' in its title) Marathon Infinity was the last and largest game in Bungie's pre-Halo FPS series. Its «Blood Tides of Lh'owon» campaign, which could be played either solo or cooperatively, offered 20 levels that included new enemies to fight and weapons to fight them with, as any FPS sequel demands.

The release of Classic Marathon Infinity represents the end of Aleph One Developers' project to bring the Marathon Trilogy to Steam. The team is named after its community developed open source engine based on the source code for Marathon 2, which Bungie released for free before Microsoft acquired the company at the turn of the Millennium. It's a similar deal to what The Force Engine did for Star Wars: Dark Forces, before Nightdive released their own, official remaster for Lucasarts' classic, anyway.

In any case, The Aleph One team has rebuilt the three Marathon games in this homebrew engine, releasing them across the course of this year (which happens to be the original Marathon's 30th anniversary). The reconstructed version of that game arrived on Steam in May, while Classic Marathon 2 hit the service last month.

All of this has happened with the full approval of Bungie, who said back in March «We're very supportive of the Marathon community and Aleph One's dedication here to bring the original Marathon to PC, Linux, and Mac for everyone to experience, with cross-platform play available in multiplayer. This is a true tribute to the original game!»

Alongside simply making the games run on PC, the Aleph One rebuilds also provide optional support for widescreen HUDs, 3D filtering/perspective, positional audio, and 60+fps interpolation. «Just in case the original is too authentic», the Steam page for Infinity wryly comments.

The Marathon Games are a real