Experience ‘The Passing’ in Left 4 Dead 2 on April 22

Expect to see Left 4 Dead 2‘s multiplayer scene get a healthy boost in player activity on April 22 — that’s when “The Passing” finally comes out for PC and Xbox 360. The long-awaited add-on has something new in store for us called Mutations.

Described as “week-long runs of new gameplay modes,” Mutations include things like Realism Versus and Chainsaw Massacre. Valve has admitted to there being at least twenty of these various modes planned, but knowing the company, I could see the support lasting even longer.

Of course, there’s also the meeting of the old survivors with Left 4 Dead 2‘s cast of characters to look forward to, plus the extra stuff you’re probably already aware of. Who’s in?