http://www.bloody-disgusting.com/news/videogames/1606/
As for the DLC, it comes free with the game while everyone else will have to toss out $10 for it. If you're still on the fence the DLC comes with four stages that can be played alone or with friends. In it you'll have to fight waves of increasingly difficult enemies. The best thing about all this is the experience you gain here transfers to the campaign as well.
