First, the bad news: it runs very slowly. The AI seems to be confused about what it should be doing tactically at times. Finally, the mission difficulty ratings need some fine tuning as well. On the other hand, if you enjoy the tabletop game, you should enjoy this. Improving your lance and warriors is an excellent time sink.
It's got a few glitches, but it's an interesting concept. I haven't seen another horror/western mashup and the poker hands/cards giving special abilities is also different. On the other hand it IS glitchy, only has a small replay value, and the campaign leads you by the nose. Buy it on sale; it comes up often enough.
I got HOMM when it came out. Then the expansions. I loved it then. I love it now. There are over a hundred games in my account. There are about six I come back to play again and again. This is one of those. The graphics are dated, but not terrible. The learning curve is not shallow, but the interactions between the factions make this game very cool. Thank you GOG for bringing one of my faves back.