Rocketbirds: Hardboiled Chicken is coming to PC via Steam later this fall. If the following promotional video is to be believed, this is one heck of a game I've overlooked. It's a 2D shooter which features Hardboiled, a super bad chicken who's on a mission to kill the evil penguins who have taken over Albatropolis.
Rocketbirds: Hardboiled Chicken has a separate co-op campaign in which players take the control of two budgie commandos. A budgie is parakeet, for those of you who are wondering. Don't worry, they're tougher than they look, and they look badass. (They're the six squat birds surrounding Hardboiled at the end of the trailer.)
Rocketbirds: Hardboiled Chicken supports two player local co-op. Look for it on PC later this fall. If you can't wait, you can always pick it up on the PlayStation Network right now.