Valve Details the Reaction and Success of Left 4 Dead 2 Mutations

With a dozen Left 4 Dead 2 "Mutations" released in as many weeks, Valve has collected a detailed breakdown of the modes developed to tweak the zombie-infested title's gameplay.

According to Valve, the most popular Mutation has been Realism Versus. The mode, which is now a permanent fixture in the game, captured the attention of 41% of all players the week it was initially released, making up for 22% of the each player's minutes when it launched. As a comparison, Survival Versus was only played by 25% of players for a total of 4% of their time with the game the week it was released.

Chainsaw Massacre was the most tried Mutation, netting 52% of Left 4 Dead 2 players during the week of its release and making up for 14% of game their game time.

Valve promises more Mutations are on the way and says they will continue to tweak past Mutations as well as bring back some old "favorites."