Valve's Gabe Newell was among the many in EA's parade of speakers during today's EA press conference. Newell took the stage to talk a bit about Left 4 Dead, and how the "Director" AI could scale gameplay in real time.

Earlier today, we saw two short demonstrations of this Director AI in action. In the first example, four co-op players weren't doing very well. They were low on ammo and inaccurate in shooting. Because of this, the Director AI scaled the game's difficulty back a bit. The group only had to fend off a few zombies.

The second example was set in the same setting, a gas station. This time around, the players were better, and were hitting targets skillfully. In this situation, the group was bombarded by several zombies rushing at them. The Director AI rewarded their sharp shooting and team work with awesome visuals of the gas station exploding. 

Newell also showed a short video that featured new character designs for the "survivors" in Left 4 Dead. We don't have any of those images, but they were mostly conceptual art anyway. Instead, we offer up new screenshots from the game in the gallery below, fresh from EA.