First impressions after an hour:
Dat intro.
I felt like the Polygon guy shooting with the pistol until I got my bearings.
Holy hell, what an optimized game. No hiccups or tearing so far - maxed out everything at 1080p on 6700K/980Ti/16GB - does not falter from 60FPS unless it's to go 61 FPS lol
The System Monitoring settings are awesome. You have an overlay that gives you as much or as little as you want - from just FPS on Low to CPU core and GPU usage on higher ones. Once I realized that it was running perfectly maxed out, I turned everything off and just enjoyed the game.
The speed is absolutely perfect and takes me back to Doom in the 90's. A LOT about this game makes me nostalgic, yet appreciative of the newer stuff that has been assimilated as well.
The Imps are annoying in the best way possible. I really love what they did with them.
This IS Doom and I really wish I didn't have to go to bed right now or get up for work tomorrow.