L4D has a new DLC called Crash Course. It is an awesome campaign. It has 2 levels. They are kinda hard but not really. It's so cool. Post your comment on what you think about it. If you have L4D and haven't tried the campaign, you should try it. It's the best campaign to me. At the end of the second level on the campaign, it is like Dawn of the Dead. You have to wait for a tricked out bus to get down from one of those car lift things to get inside. You will have to start the power generator twice.