EatChildren
Currently polling second in Australia's federal election (first in the Gold Coast), this feral may one day be your Bogan King.
From the little I've played (first level) the framerate issues to me seem somewhat linked to the alphas, especially relative to dynamic lighting, like they're being sampled at a very high rate. Looking at a truck's lights while smokey alphas pass over the front will chew off 15 - 20 fps on my 980 Ti. And one sequence, where you look through a digital window thingy into an interrogation room, took my fps down to ~45fps. As soon as it broke it shot way back up to like 120+.