Yesterday, Phoronix had encouraging news about the prospect of Steam for Linux: photo evidence of Left 4 Dead running on Ubuntu 11.10 with AMD Catalysts drivers. Today, the site followed up with video footage of that same scenario, posting a hastily shot clip to show that Valve is indeed making progress -- slow as it may be -- on porting the game engine to Linux. Got 14 seconds? Check out the video demo below the break.