Expect lots of portal gun shenanigans from your co-op buddies.
The introduction of cooperative gameplay in Portal 2 has us excited. Little is known about how things will work with two players, each with his (or its) own portal gun, but GameTrailers has the exclusive teaser trailer from Valve giving the first look at coop.
From it, we gleamed that it'll be a robot duo with dual portal guns. If only February 9, 2011 could be here sooner.