so I was thinking about L4D, and how cool it would be when Valve releases new "Movies", if they were sequels to the previous maps? like No Mercy 2: Zombie Boogaloo, and it picks up from the chopper, which goes down on the other side of town or something... Or Death Toll 2: Caution, Bridge Out , you reach the open water, only to have the engine die, and then drift towards a huge tanker thats also adrift....

OR, the new 'movies' are a trilogy and each builds off the other, and has your group trying to find the source of the infection (maybe an evil genius?) or to find the cure....

I am loving the individual movies - it just struck me that they could really leverage the idea into episodic content about the L4D world and tell a bigger story than just one stand alone adventure for each movie.