Here are my comments:
1. The Dead King's Cloak, which spawns liches at machine-gun speed, seems to be useful only in situations where it's absolutely necessary. In any other case, it simply breaks the balance. The first time I played, I used it, thinking that something really terrible was ahead, but it turned out that I could have managed perfectly well with what I got from the captured castles, which was a bit disappointing. The second time, I played without it.
2. The idea with the dimensional door is quite understandable, but it seemed to me that because of it, the Dungeon became too empty. And the first time, I had to click on it randomly, which wasn't very interesting.
3. The enemies seemed too static to me. Although the AI in Heroes games isn't particularly smart, this rigidity only makes things worse. I'm not talking about the quest heroes; everything is clear there.
4. I also think that there are too many artifacts, especially assembled ones. They lose their value when they are already assembled and lying around in corners. It's more interesting to find them in parts.
I don't remember anything else. Overall, I really liked it, especially the hidden portal behind the volcanic smoke; that was a great joke