Here is my feedback:
I used a lvl 47 (can;t remeber what level I was when I entered) Destroyer on Hard difficulty. Only thing on him that is not vanilla is the Wind wall, which I never used as there were no archers inside.
I had extremely hard time to get to floor 2. Even with 889-1777 damage absorbed by my armor pieces and the fact that Frost shield absorbs 54 % of elemental and physical damage and the fact that my finger was stuck to Heal All VI I had to drink about 25 potions to make it to level 2. Of course despite the micromanagement I died 3 times the same embarrassing deaths from fire elementals. I had to pull and run back all the time. Plus I had to make sure my dog was transformed to something powerful from fishing all the time. I can absorb unbuffed about 500 of each elemental damage but only 200 of fire damage (not counting the frost shield of course, neither the elemental protection spell), so overaggroing too many fire elementals means certain death for my destroyer.
On level 2 I encountered the same problem as testers above mentioned. There is no way to pass the electric barrier. No crystal to break whatsoever.
In any case it was a true test for our skill, my fingers hurt right now
Music has something twisted which I like and the entire concept is really atmospherical. Waiting anxiously for a fix.