Now that they’ve released the first 12 Mutations, Valve wanted to take a minute and talk to the community about the Mutations.

Overall the Mutations and weekly polls have been a great success and an amazing way for us to get feedback from the community. Don’t worry, we still have more Mutations coming and we will also be tweaking and bringing back some of our favorites.

The idea behind the Mutations was simple. Left 4 Dead 2 is played by many different players and types of players. Some players have 300+ hours played in almost daily games and some players only play in weekly casual games with friends. We wanted to create weekly events that mixed up the game rules to experiment with gameplay and made people look at the game in new ways.

Before Mutations, what got played the most? It really depended on the day. Versus and Co-op Campaign were tied neck and neck each with around 40% (80-85% total) of the players on any given day. The other 15-20% was split between Survival, Realism and Scavenge.

Some of the constraints we decided on when creating Mutations: It was okay if it wasn’t something that you wanted to play enough to replace an existing game mode as long as it was fun for a short period. Not every Mutation was going to appeal to everyone. Some Mutations would be directly aimed at smaller demographics inside the larger player base.

The decision to make Realism Versus permanent was easy. 41% of the players that week tried it. It grabbed an impressive 22% of the player minutes the week it was featured. That compares to the similar but different Survival Versus which was tried by only 25% of the players and was played for 4% of the player minutes the week it was featured.

Chainsaw Massacre was the most tried Mutation with over 52% of the players that week giving it a try and it was played for almost 14% of the player minutes that week. The voting pattern for encore weeks became obvious; the most played Mutation of the four received the most votes. The results of those polls were often a surprise for the forums but with a sample size for some polls reaching almost half-a-million votes these responses, by statistical necessity, reflect a more stable measurement of player sentiment.

They then talk about the percentage breakdown on the 3 most played Mutations, for players who got into a match at least once:

52% Chainsaw Massacre
45% Last Man On Earth
41% Realism Versus

And the percentage breakdown on the Mutations that had the most player minutes during their featured weeks:

22% Realism Versus
14% Chainsaw Massacre
12% Last Gnome on Earth

And they give “Hard Eight”, an underrated mutation a little shout-out, leading them to their final point:

The “You should have tried it because you would have loved it “ honorable mention goes to Hard Eight which was only tried by 26% of the players but hit 12% of the player minutes that week.

Hard Eight leads us to our last point. Not sure about a Mutation? Try it. Too often we see people dismiss a Mutation before they play it only to play it and then request it be made permanent. The only way you can be sure if running scared from multiple Special Infected is fun or not is to give it a try.

Yeah, it’s a shame. Stand by, cause in the next few hours we’ll be seeing the next Mutation Week.