Honestly, it runs on the lighter side when it come to UE4 games. I can maintain over 100 fps on my modest rig up until there's over 10 enemies fighting me at once. And even then I easily stay above 60.
Viewing post in BETA 0.3.2 Update [Major Polish & Bug Fixes] comments
I ran it and it runs fairly good, a bit choppy during action moments, but I don't think it's the game causing that. For some reason, the look sensitivity was stuck at 0.5, so it was difficult to move around. I did get through about 3-4 levels despite that. Couldn't find any bugs besides clipping and objects/SWAT guys stuck in floors or walls.
I do like the Half-Life inspired mechanics too, especially the gravity gun hand thing going on and the health stations. Pretty cool game overall!