L4D2: The Passing coming to Steam and XBL Thursday [Update]

Update: Valve has detailed The Passing a bit more, citing the single-player, multiplayer and co-op modes that will be present in the DLC. It will also include weekly game mode events called "Mutations." These week-long runs of new gameplay modes range from "Realism Versus" mode to "Chainsaw Massacre," which gives all players chainsaws with an unlimited supply of gasoline. YES!

There are over 20 Mutations planned, each playable on all L4D2 Campaigns. Mutations are exclusively available to owners of "The Passing" DLC.

It will run you 560 MSP on XBL and will be free for PC.

More below the break.

Original: Valve promised it would be released this week, and now it looks like The Passing is set to arrive Thursday for Left 4 Dead 2.

The information was confirmed through two sources: Major Nelson and a tweet from Xbox Live Editor, Daniel Maher (via Ve3tro).

Good. Now we can wonder no longer.

Here's the PR blurb.

• "The Passing" offers a new co-operative challenge mode of play, support for infected bot play in Versus, a new "uncommon common" zombie class (the fallen survivor), melee weapon (golf club), and firearm (M-60).

• Available for 560 Microsoft Points on Xbox 360 and free on the PC, "The Passing" takes place just after the Dead Center campaign of L4D2. Set in a small town in rural Georgia, players assume the role of the L4D2 Survivors as they meet with the L4D1 characters.

• Exclusively available for Xbox 360 and the PC, L4D2 sets a new benchmark for co-operative action games. The title adds melee combat to enable deeper co-operative gameplay, with items such as a chainsaws, frying pans, axes, baseball bats, and more.

• With the AI Director 2.0, L4D's dynamic gameplay is taken to the next level by giving the Director the ability to procedurally change weather effects, world objects, and pathways in addition to tailoring the enemy population, effects, and sounds to match the players' performance. The result is a unique game session custom fitted to provide a satisfying and uniquely challenging experience each time the game is played.

• Finally, with new Survivors, boss zombies, weapons, and items, Left 4 Dead 2 offers a much larger game than the original, featuring more co-operative campaigns, more Versus campaigns, new Survival maps, and the new competitive game mode, Scavenge.

Achievements for the game popped up earlier today on the official L4D blog, which pointed to some new game elements - now we all know what they are.