Why the developers behind Left 4 Dead and Evolve love making co-op games

Something seemed to light up inside Chris Ashton and Phil Robb when I asked them why they like making cooperative multiplayer games.

It was seven at night, and the two co-founders of developer Turtle Rock Studios were only hours away from ending a long day of showing journalists the latest version of their alien-hunting game, Evolve. Coming to PC, PlayStation 4, and Xbox One later this year, the co-op shooter has four players trying to track down and kill a fifth player who’s in control of a giant monster.