sentences:  In 2009, the small indie game company Entourev LLC published Voltley to Linux which is the first commercial exclusive game for this operating system.In the same year, LGP released Shadowgrounds which was the first commercial game for Linux using the Nvidia PhysX middleware.In July 2012, game developer and content distributor Valve announced a port of their Source engine for Linux as well as stating their intention to release their Steam digital distribution service for Linux.