Left 4 Dead 2 will be entering into its Linux version very shortly, integrating it with Valve’s ongoing “Extended Mutation System” beta. What is EMS exactly? Essentially, it’s an easy way for modders to change various scripts within the game, totally customize them however they choose, and so much more (not to be confused with the Steam Workshop). Up until now, this system has only been available in very small testing groups, but that’s about to change very soon.