The higher difficulties (5+) feels poorly tuned. Enemy damage scales much faster than you can realistically out-blessing your shields, all of the defensive options cap out at much lower shield amounts than the damage you are getting hit with, and sometimes even what look like perfect parries still make you take damage (and that's on an orange + parry sound).
The mechanics outside of that aren't bad, but that particular combination makes things very unpleasant.
There might be some ways to get around this but you'd have to do an insane amount of grinding to push shields or damage to margins where the above doesn't feel like a slog through levels or ore. I might be missing something: perhaps a better level of defense than Priest garb, or there's a way to get the true version of the previous hero's sword.
But at least where I am (Second replay, beaten the boss, level 76) the second dungeon is just either running around demon orcs and spamming skills for battles that take too long, or chaining 10x the hits with perfect parries they have only for one of their strikes to damage me on a parry, get knocked down, and start to get tired of the whole process. Can I do it? Eventually. But having to do the same thing repeating while whittling down boss orcs that can take 5+ minutes a fight (unless I risk the damage-through-parry)? Tiring.