Left 4 Dead is obviously not the first game to use environmental story telling but considering the fact that its a multiplayer game that's almost completely void of any cutscenes, I can't help but adore left 4 dead's style of story telling. The Parish and The Sacrifice are the head and shoulders best campaigns from a story perspective but I think the Parish edges out ever so slightly.
The fate of the l4d2 survivors being a complete mystery is the biggest takeaway from making this video. The fact that we will likely never get a definitive answer as to what happened to them is easily the most frustrating thing about the Parish.
yea.... they're probably dead.