Valve just stuck out a promo for L4D2 DLC The Passing, showing characters from the game's first and second installments sparring on a bridge... with words.
The skit features Francis from the first game and Rochelle from the second, talking about how they hate bridges. It's well funny. To be honest, it's not that funny, but it's about as funny as things get in games, so just shut up. You ungrateful idiot.
The Passing main meat is a new co-op challenge mode, support for infected bot play in Versus, a new “uncommon common” zombie class, melee weapon (golf club), and firearm (M-60).
The content also includes "Mutations" - events, basically - of which 20 are planned over the coming weeks, each playable on all L4D2 Campaigns. Mutations are exclusively available to owners of The Passing.
It costs 560 MSP on XBL and will be free for PC. This trailer says it's out now, following promises earlier this week that it'd release today.
See for yourself.