Updates to Left 4 Dead 2 have been released. The updates will be applied automatically when your Steam client is restarted. The major changes include:

Left 4 Dead 2
Fixed stability problem during level transition experienced by some users
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Call of Duty: Modern Warfare 2 (PC)We run the map and show off a few secret spots you won't want to miss.
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With exciting new content across the board and plenty of it, Left 4 Dead 2 outdoes its predecessor and makes the zombie apocalypse an absolute blast.
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Chris Watters welcomes the zombie apocalypse in this video review for Left 4 Dead 2.
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A survivor grabs a guitar and goes to work.
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The team of survivors rallies around a WC in the park.
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The survivors fight off a horde of zombies while trying to fill a car with gas.
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North American Retail and Steam Available Now, Rest of World Follows Later This Week

Nov 17, 2009 - Valve, creators of best-selling game franchises (such as Half-Life and Counter-Strike) and leading technologies (such as Steam and Source), today announced the availability of its zombie thriller, Left 4 Dead 2, at retail outlets across North America (360, PC) and worldwide via Steam (PC). Retail outlets around the world will launch the title later this week.

Exclusively available for the Xbox 3... [read more]

The sequel to the best-selling and critically-acclaimed co-operative multiplayer thriller, is now available via Steam to gamers around the globe. The title will be available for the PC and Xbox 360 at retail stores on Tuesday, November 17th in North America, and worldwide throughout the week. For more information, please visit www.steamgames.com.
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Left 4 Dead 2 (PC)One click separates you from the answer.
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