so i downloaded this add on campaign which is almost exactly the same as silent hill on the playstation 1. its really awesome...
it gives L4D its fear factor back without a dought. its only co-op campaign. but it is really worth it. i reccomend this campaign!!!!
http://www.l4dmaps.com/details.php?file=865when you have dl'ed the winrar thing. just extract it to the following -
C:\Program Files\Steam\SteamApps\common\left 4 dead\left4dead\addons
and you should have it up and running.