As far as interviews go, not too much has gone unsaid about Left 4 Dead. However, there are times when a few undiscovered nuggets of goodness see the light of day. CVG had a chance to interview Valve's Chet Faliszek on the history of Left 4 Dead and how the game, as we know it, came to be.
Let's talk about the role of the boss Infected...Feel free to read more from Faliszek courtesy of CVG.
Faliszek: Well, that's changed greatly, especially since we split the game in two. Originally, the whole game was basically Versus mode, with people playing as boss infected. Originally we wanted the director to control everything, which meant that if you were a good infected player your reward was more time spent not playing, which wasn't a good reward. So with Versus split off we've been able to tweak things substantially.
I don't know if you noticed but the maps are slightly different for the Versus mode. The ammo room on the finale of No Mercy, for example, has more access, so it's harder to defend. In co-op mode these are just easier or harder parts of the map, but in Versus it becomes exploitable, so that's less fun and we have to deal with that. Now [with pure AI co-op campaign] we're also faced with how to do difficulty overall - how would you do it in TF2? It's down to who your opponents are. In Versus there are skills you learn and there are a lot more combinations of talents than you might think.
You end up having to be a much better survivor team, because player Infected get to be so inventive. Who you attack and how you attack them is a big deal. We put a lot of work into that.