Thought i would write up some first impressions after playing DB for about 3-4 hours.
First off… its FUN and that cannot be understated, fast paced rewarding combat - it definitely reminds me of ET and ET:QW (indoors).
I started by tweaking the settings to get a solid 60 fps, I ended up putting it on low - but quite honestly I couldn’t tell the difference, it still looked great - loving the art style. Also the death-ghosts are a very nice (and unexpected) addition - especially when you have been sniped in the groin!
So to begin I found myself using iron-sights at way too closer range, and they really aren’t needed unless at high range (which is good). I also tended to find my way easily with teammates to follow, but not so much when I spawned on my own. A few times (especially when on defense) I ended up running to the objective indicator only to find it was on the other side of a wall.
Two things that stuck out initially were grenades and turrets. I am used to throwing a grenade or putting a turret down and expecting kills, this doesn’t really happen in DB. A few times I have been like… oh somethings shooting me… ohhh its just a turret… “shoots a few bullets and knocks it over” 
The objective based combat is just as fun as ever, which some decent variety over the three maps available. I especially like White Chapel - with the authentic weather too. Overall my first impressions are pretty good, there’s a lot to like about DB!