The Demon might seem powerful, but with a good army, it becomes an easy target. It can be easily defeated in one and a half turns while it's trying to open portals. It seems like it needs buffs, but there are no specific ideas yet.
Subjectively, the underground is too extensive; some unnecessary parts should be cut down and points of interest compressed to make everything more accessible.
Overall, it's a very pleasant and well-designed map, without being overly drawn out, but also without much risk of losing (which is скорее a plus for me as a casual player).
Regarding additional quests, artifacts, and upgrade options, everything is good; regarding the main quest, it's quite decent too. I can't say that I got a "wow" effect; it's just done at a very decent level (no, it's not simple). There are very few maps that are made well and don't annoy you. It was nice to spend time on it.
As for the "wow" effect, I think it's very difficult to achieve now because a lot of time has passed since the game was released, players are already experienced, and besides, it's quite subjective.Now, about some oddities:
1. The blinding spell from unicorns strangely affects the guard vampires – they don't respond to the attack; in the log, I see the blind effect, but it doesn't apply (and shouldn't, as they are undead).
2. The portal guardian to the elves in the underground with a large army (Randall?) disappeared at some point; I didn't notice any specific trigger. At the same time, the quests "do not engage Randall in battle" and "capture Coldwell" remained open until the end; I won without completing them. There were no blue heroes/cities on the map, but their objects remained blue. Maybe this is normal behavior overall, but it seemed not very intuitive.
3. An elf hero (I had Ossir there) got blocked by caravans between the last city and the garrison (the city has 3-4 caravans, the hero, followed by another 3-4 caravans at the garrison). He stood like that for several weeks. Perhaps the passage needs to be widened