Valve's first expansion to post apocalyptic zombie shooter Left 4 Dead 2 makes one appreciate the developer's gift with wordplay and just how important being able to see through walls is when battling the infected.

The Passing brings new things to Left 4 Dead 2, including a new three-level campaign set in a wet Georgia town, one new firearm (the incredibly satisfying M60 machine gun), one melee weapon (a golf club), a new "uncommon common" zombie known as the Fallen Survivor, and the new concept of Mutations. The last item in that list offers weekly variations on Left 4 Dead 2's various game modes. The initial Mutation is "Realism Versus," which makes life as a Survivor much more difficult when playing against human-controlled Special Infected opponents online.

The downloadable add-on, released on the Xbox 360 and PC, also offers a passing encounter with the Survivors of the original Left 4 Dead, tying the two games more closely together.

Loved
The Fallen Survivor: It may be a small and rarely encountered addition to the ranks of the infected zombie masses, but The Passing's Fallen Survivor introduces an unexpected twist. Because the Fallen Survivor often drops coveted supplies like pain pills, health kits and Molotov cocktails, he's an attractive target. But he's also a target on the run. Unlike Left 4 Dead 2's other zombie types which crowd the player and warrant cautious progress, the Fallen Survivor forces the player to make chase, abandoning caution and ammo conservation, changing the tactics players must use.

Mutations: It may be too early to say just how successful Mutations are in the long term appeal of The Passing, since "Realism Versus" is just one of more than 20 planned variations on established game types. But "Realism Versus" is a thrill in itself and the promise of unlimited use chainsaws in the game's Campaign mode, among other mystery rule changes, assures that I'll be checking in weekly to make sure my copy of Left 4 Dead 2 gets properly mutated.

Hated
Uncommonly Common: While the new campaign brings with it fresh maps on which to play the gas-guzzling Scavenge mode and multiplayer Versus matches, the campaign itself feels a bit flat. The Passing is lacking in much of the unique appeal that made Left 4 Dead 2's other chapters so exciting. The three-level campaign borrows some of the highlights from previous levels—Hard Rain's thunderstorm, Dead Center's fuel grabbing finale, The Parish's sewer slog—but doesn't itself present anything quite as memorable. Your encounter with the original Left 4 Dead squad also feels strangely unsatisfying. Fortunately, the rock solid gameplay and new variations on what was already immensely enjoyable in Left 4 Dead 2 alleviates the comparatively ho-hum campaign.

Anyone playing Left 4 Dead 2 on the PC needn't think twice about spending the bandwidth and time to download the free expansion pack through Steam. The new additions and the promise of even more variation in the game's rule set guarantee that The Passing will keep zombie slaying enthusiasts entertained week after week for months to come. The M60 machine gun, so satisfying to unload on a horde of infected, may alone be worth playing The Passing.

For the Left 4 Dead 2 player spending 560 Microsoft Points ($7 USD), worry not about the complaints about the campaign's shortcomings, for its only be compared to the very impressive offerings included in the original release. Expect instead to enjoy its Versus mode on new maps and, through Mutations, to get the most out of your purchase. Also realize that you'll probably be sold on downloading the follow-up chapter coming to the original Left 4 Dead, if only to see how Bill, Francis, Zoey and Louis made their way so far down south and to learn what goes wrong along the way.

Left 4 Dead 2 The Passing was developed and published by Valve for the Xbox 360 and PC on April 22. Retails for 560 Microsoft Points on Xbox 360, free on PC. A copy of the game was given to us by the publisher for reviewing purposes. Played through campaign multiple times on normal and advanced difficulty, played all game types, with the exception of Survival on The Passing exclusive maps.

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Left 4 Dead's world is a miserable one, no? Ruins, and darkness, and more ruins, and zombies. What the game needs is a break. A break in space.

Mapper Aigik has come up with Contact, a Left 4 Dead 2 map that puts both zombies and survivors in a sci-fi setting, with fancy lighting, holograms and planetary bases. Like Metroid Prime, then, only without a suit to save you from the rotting jaw of the living dead.

You can grab it here, but be warned: in terms of both performance and zombie AI, it's not quite perfect.

Contact: A gorgeous Left 4 Dead 2 Scavenge map set in space [PC Gamer]

Players passing through an abandoned pool hall in Left 4 Dead 2's The Passing might catch a glimpse of the last words of a Capcom character who has covered wars, you know. Possible Dead Rising spoilers ahead?

Behold the final words of Frank West, another victim of the zombie apocalypse. Left without film, without a helicopter, and ultimately without hope. Of course things might have turned around for him in that final day, but whenever he wrote this, things must have looked pretty bleak.

You have to love the little cross-game nods, don't you?

For those curious, keep your eyes peeled during chapter two.

Frank West's Left 4 Dead 2 Cameo [Destroyed Controller]

Left 4 Dead 2's "The Passing" will bring together the survivors from Left 4 Dead 1 with the survivors of the second game. Just because they're all surviving, though, doesn't mean they're going to get along.

The Passing will be out later today on both Xbox 360 and PC. It'll be 560MSP on Microsoft's console, while PC owners can enjoy it for $0.00.

Left 4 Dead 2's "The Passing" will bring together the survivors from Left 4 Dead 1 with the survivors of the second game. Just because they're all surviving, though, doesn't mean they're going to get along.

The Passing will be out later today on both Xbox 360 and PC. It'll be 560MSP on Microsoft's console, while PC owners can enjoy it for $0.00.

Here's the original poster for Left 4 Dead 2's new downloadable content, The Passing. Below you'll find the new version Valve has just released, which is missing one key element. Potential spoilers ahead!

Keen-eyed Kotakuite M.u.s.o.u.k.a noticed a change between the original poster and the new one that's appeared on the official Left 4 Dead 2 blog. See if you can tell the difference:

That's right, only three of the original suvivors are silohuetted on the right side of the poster, while previously all four were represented.

We knew that one of the original survivors wouldn't be making it to The Passing, but we weren't sure who. In the upcoming downloadable content for the first Left 4 Dead, the choice is left up to the players. In the Left 4 Dead 2 DLC, Valve has made the choice for us.

You guys see Zoey anywhere?

Now, as Crecente points out, Zoey might just be very slow, and hasn't arrived yet, but I'm thinking that slow and Left 4 Dead don't mix, and Zoey is no longer a going concern.

We'll find out for sure tomorrow, when The Passing goes live for the Xbox 360 and PC.

Update: Folks are reporting seeing different characters left out of the poster than the one we seem to be seeing. I've tried three different computers so far, refreshing on a regular basis, but have only seen Zoey missing so far.

While confirming a Thursday release date for Left 4 Dead 2's "The Passing" downloadable content, Valve also reveals "Mutations," featuring more than 20 new game modes rotated on a weekly basis, from "Realism Versus" to "Chainsaw Massacre."

It's official: Left 4 Dead 2's The Passing will be out on Thursday, April 22 for the Xbox 360 and PC, and it's much more than a new episode, new infected, and a couple of new weapons. According to Valve, The Passing will also include a brand new way to play the game that'll keep players coming back every week for more.

"Mutations," are a series of new game types that Valve will be cycling in and out of the game on a weekly basis. There are more than 20 different "Mutations" planned, including the aforementioned "Chainsaw Massacre," which arms players with chainsaws and an unlimited supply of gasoline.

Now that's my kind of zombie slaughter right there.

All new game modes will be playable on any of Left 4 Dead 2 campaigns, and will be exclusive to players that have purchased The Passing downloadable content.

Purchased being a relative term, of course. Xbox 360 players can expect to pay 560 Microsoft points ($7) for The Passing, while PC players can purchase it for completely free, which I suppose doesn't count as purchasing it at all.

Two teams of survivors means twice the trouble for the ravening hordes of infected in Valve's Left 4 Dead 2 this Thursday, when The Passing downloadable content finally shows up on Xbox Live.

Originally scheduled for late March, The Passing's release date was narrowed down to this week last Friday, and now Microsoft's downloadable content schedule narrows that down to the 24 hour period between Wednesday and Friday.

That's Thursday, in case all of these clues I've been dropping stumped you.

As of this writing we're still waiting on official word from developer Valve, but we assume the PC version will hit Steam around the same time.

Xbox LIVE Marketplace release schedule [Major Nelson]

Valve's seems quite serious about releasing Left 4 Dead 2's first expansion, The Passing, this week... or, according to today's update, "soon." So it's probably high time we find out what those new game modes are.

While Valve still isn't telling, officially, it's hinting at new changes to the game in a new update at the official Left 4 Dead blog. They warn that things could get spoiler-y, if you're overly sensitive to these types of things, so consider it noted.

One new mode may be called "Mutations." Hey, it's one of the Achievements, requiring that players play through six Mutations to secure the Mutant Overlord achievement. And unfortunately, that's the extent of the detail they provide. Another may involve the opening of foot lockers—not to provide zombies with quality footwear, but to, presumably, find well-stocked weapons caches.

Read on for more potentially spoiler filled details, then hurry up and wait for more info later this week.

Passing an Achievement [Left 4 Dead Blog]

The first downloadable episode for Valve's southern fried zombie shooter Left 4 Dead 2 didn't make its originally scheduled "late March" release. Thankfully, it looks like "The Passing" campaign will make a late April release.

Valve updated the official Left 4 Dead 2 blog today with good news—The Passing, a new campaign set between the levels Dead Center and Dark Carnival in a small Georgia town, will arrive "next week." Presumably, that means on both Xbox 360 and PC, as has happened with prior downloadable Left 4 Dead content.

The new episode brings with it one new zombie type, the "uncommon common" Fallen Survivor, a handful of new weapons and new game modes, as well as a chance encounter between the survivors of Left 4 Dead and Left 4 Dead 2.

Worlds Collide! [Left 4 Dead Blog - thanks, Tom!]