Left4Dead 2 has been announced exclusively for Xbox 360 and PC, and will be the subject of Valve’s biggest ever marketing push.

The sequel to Valve’s highly popular 2008 zombie shoot-‘em-up was unveiled at Microsoft’s E3 press conference via a new trailer, and will be released on November 17th, 2009.

The original was supported by a marketing campaign that cost more than $10 million. Left 4 Dead 2 will be launched worldwide with a multi-million dollar marketing campaign across TV, outdoor and online.

"Left 4 Dead was backed by our most aggressive advertising campaign to date, and resulted in a top 5 showing on two platforms during holiday 2008," said Doug Lombardi, VP of marketing at Valve.

"Left 4 Dead 2 is a larger game and will be supported with even more consumer and retail advertising programs than the original." 

The game will feature new survivors, boss zombies, weapons and items, as well as more co-operative and versus campaigns. The Director will also have more control over the game, including weather effects and world objects.