Metro: Last Light has just been released for Linux, and will see full, dedicated support for Steam OS whenever that's out next year, Deep Silver and 4A Games have confirmed.
According to the studio and its publisher, 300 members of the Steam community chosen to receive prototype Steam Machines will find a copy of Metro: Last Light included with their hardware to test it out.
“We are excited by the prospect of bringing the ultimate Metro experience, powered by next-gen PC hardware into the living room,” said Oles Shishkovstov, Chief Technical Officer at 4A Games. “Metro: Last Light will be a great showcase for Steam OS and the Steam Controller.”
Additionally, the game already supports Steam Play, so owners of any Steam version will automatically find the game added to their Windows PC, Mac, and Linux Steam libraries.