How Evolve learned from Left 4 Dead's AI director

Turtle Rock's upcoming next-gen game Evolve is all about the hunt, pitting four humanoid characters against one powerful monster player. But even though everything is driving toward a confrontation, that won't be the end of the match. In an interview, studio heads Chris Ashton and Phil Robb explained how lessons learned from Left 4 Dead will keep the pacing on-track.

"If you played co-op [in Left 4 Dead], it very specifically had a very roller coaster ride to it, where things would slow down, things would get quiet, and then things would go batshit crazy," Ashton told Game Informer. "That system was dynamic, that was the AI director. We're doing similar things in the game [Evolve] to control the pacing. There's underlying systems in play and what happens is the game works out so that you're tracking the monster—trying to find him, trying to find him. He's trying to eat. And you're all in this kind of slow moment but eventually you come together and you fight."

"But the game is designed so it doesn't end there, he's going to get away. So the question is how much damage did you do? Did you get the upper-hand? Did he get the upper hand? What's going to happen next? So you separate again, and the pace slows down again, and then you find each other again. Most games you have four or five confrontations."

Robb added that it's possible for one side to win in the first encounter, but it's not ideal. For that reason, Ashton says, they've set up "systems under the hood" to facilitate escape, so whichever side is losing can regroup and plan its next move. Maintaining that sense of slow build-up is important to the team.

"You need to have those peaks and valleys, right?" Robb said. "It's about contrast. You can't appreciate the action unless you have some inaction."