GameInformer.com has an article on Division 9, a co-op zombie shooter that was left for dead long before Left 4 Dead was released. They have quotes from Ken Levine and other Irrational staff describing a game that had base-building functions, strategic decision making, and relentless waves of zombie attacks. The article also includes a trailer showing off some demo gameplay. Word is the game came this close (picture two fingers very close together) to production, as they sold the game to Vivendi in a deal that was nixed by the sale of Irrational to Take-Two.