The weekly mutations continue with Valve revealing the new ‘Follow the Liter’ mutation for Left 4 Dead 2. Valve describe the mutation as “No more fighting over what cans to grab first. This Mutation spawns only one group of cans at a time, so survivors know exactly where to go. There is only one problem: the Infected know exactly where they are going.”In other mutation news, Valve has decided that the Realism Versus will be made permanent following community voting. The results were conclusive with 68% voting ‘Yes’, 21% ‘No’, and 11% had ‘No Opinion’. Next week Valve will reveal exactly when the Realism Versus mode becomes permanent.