Ok...sorry for spam
I don't think cheese played l4d

from http://www.maximumpc.com/article/news/e3_2...5_new_campaigns

In Left 4 Dead, when we started talking about new characters, all of a sudden we were talking about maps, then all of a sudden we were talking about campaign, and then director 2.0, hey, we're in the swamps.

Shack:  What price-point should we expect?

Doug Lombardi: This is a full sequel.

Shack: So full price?

Doug Lombardi: Yeah. At the end of the day, this is going to be a bigger game than Left 4 Dead. It's five campaigns versus four, all five are playable in Versus mode, Survival mode out of the box, the new multiplayer game mode. Plus over 20 new weapons and items. It's a full sequel.

Shack:  Flamethrower? Not saying?

Chet Faliszek: No. We like fire though.

basically the first l4d was made to be their test product. took players feedback and suggestions, and use them to make a sequel. instead of making adjustments through their steam client (one of the big reasons for having steam) as promised, they're gonna charge us for it.