Portal 2 Co-Op Teaser Trailer

The cooperative portion of the game features different characters, challenges, and story than the single player portion of the game (0:35)
Valve has released a new movie for Portal 2 showcasing this sequel set to be available on February 9th, 2011, for PC, Mac, Xbox 360 and PS3. Details on Portal 2 coop will be revealed (and shown) next week at PAX in Seattle, WA.