Spent some time with it, so figure I should record some semi-first thoughts!
You've completely nailed it from a sound and visual design standpoint. I wish you could've been there when I bust out into laughter on the 'spell' cast animation- though trust me, this was a good thing.
On Difficulty- I'm going to echo diabolodev, and say that i'd prefer an emphasis on kit than grinding for permanent upgrades, and a little polish on Serums and Boxes. Gunplay I acknowledge is probably meant to feel the way it does, but it could definitely use a minor to modest buff for how hard ammo is to find (or just make ammo VERY modestly more available, and leave stats as is- I'm sure plenty of people will poke and prod at it).
A little (and I do mean a LITTLE) visual clarity might also help- like giving the Carnifex different stances for its specials. Miiight have just lost a run to the nearly 300 damage in a straight line, thinking it was the AOE. Definitely not a factor. Nope. :P
All in all, though! I'm pumped as hell for release, early access or otherwise, and shout out to ABG for pointing me this game's way! :>