The team was also floating the idea of a "first-person wizard combat" title but it turned out "geeky in that it was kind of complicated." Left 4 Dead was originally 'Terror'.
In the video interview they also detail what went on with the collapse of publisher THQ, which led to their Evolve IP continuing under 2K Games.
Valve acquired Turtle Rock in 2008 but a year later would see them become an independent studio again and free to pursue their own IP. Studio bosses Chris Ashton and Phil Robb spill the beans of history on Turtle Rock in this Game Informer. Evolve releases on PC, Xbox One and PS4 this year.