For anyone that doesn't know these games, imagine Doom but medieval dark fantasy. And yes, they are THAT good. For people that already knew them, this is a glorious remaster and they work so good and smooth in modern systems and higher resolutions. And the new soundtrack mix (you can still choose the classic one if you prefer) is the icing on top. What the people at Nightdive are doing with these old masterpieces is insane and they deserve all the love and recognition for it.
As someone who played HoMM III since the good old days, I've always valued highly the respect for what was in the original game and its expansions. That's why I used to grow tired of other mods sooner than later, since most of them go very far with the changes and additions for my taste, sometimes even obliterating the game's balance to favour a "go crazy" experience. But that's not the case with Horn of the Abyss. This one could very well be considered another true expansion, building on top of what the game already offered in all its glory while fixing and improving some elements. The new contents are also fantastic and fit very well in the game, even if the latest new faction addition (Factory) could probably be considered a bit "off" by the most fantasy-hardcore fans. Still, its steampunk "Wild Wild West" vibe remains at a relatively safe distance from the "actual sci-fi" tag, if that's of concern for anyone reading this. This mod is really well crafted and I can't recommend it enough.