According to Phoronix, the demo version of the game contained various Linux libraries, including one called, "steamclient_linux.so" which Phronox says can do without either the Windows client or the Linux server version. In the meantime, the Left 4 Dead demo in question has disappeared from Valve's servers, and the full version of the action game appears to have no trace of the Linux data.

Valve uses its Steam platform to mainly market its own games, with an increasing amount of games coming from third party producers. Beyond that, Valve provides easy maintenance and enables communication between gamers. Valve's legal restrictions require registration before games can be activated and access to Steam is via a special client that at present is only available for Windows. A conversion to Linux would be the first sign that Steam in future might be offering (commercial) Linux games on its platform.

The rumors have been strengthened by two recent official announcements. Firstly, on its employment opportunities page, Valve Software advertised a vacancy for a software developer with Linux experience, able to "port Windows-based games to the Linux platform." Then in May this year, Running With Scissors CEO, Vince Desiderio, announced in an interview that the third part of the game series Postal would also run on Linux. The game itself is built on the Valve Source engine, as are a multitude of other games. Linux compatibility of the Valve engine could mean that soon a huge number of popular games will be available to Linux users.

Valve has not yet made any official comments about its Linux ambitions. If Steam can or will provide Linux users with high quality games in the future, remains to be seen.