Unlike the movie and music industries, which leave you in no doubt you're watching a McG picture or listening to a Lady GaGa record (and in my case leave me wondering why), videogames haven't always been great about acknowledging the people who deserve the most credit.
So it's nice to see Valve paying tribute to the AI director. He's the king of Left 4 Dead, the unseen hand on the panel of instruments that determine the flow of infected zombies into your four-man team's path, and in Left 4 Dead 2 he can punish you in tons of new ways - he has new special infected to divide you up and drive you into peril, he can smash you with storms and force you down new paths - all the while he continues to shape and reshape the pace and tone of the adventure with an intelligence that belies the fact he's just a bundle of scripts and programming routines designed to mess you about.
A lot of developers would keep quiet about him, and leave you to draw your own conclusions, but Valve's proud of him. Left 4 Dead 2's their product, but the AI director's their baby.