Heroes of Might and Magic III takes place in New World Computing's world of Might and Magic and Heroes of Might and Magic. Chronologically, it is after Might and Magic VI, but before Might and Magic VII, while the expansion should take up after that, with Heroes IV taking up next, at least that is the way it looks right now. For a description of Heroes II, and therefore the underlying system of Heroes III, check out the Mangoweb review Here. This review will concentrate only on the changes in Heroes II that are in Heroes III.
The single greatest enhancement over Heroes II is in the graphics department. While I continually say that I don't care about graphics, they certainly help to liven up the game here, and reduce the comic-book like battles of Heroes II. The hero portraits are also much better. In HOMM II, my friends and I would laugh at the pictures of nearly every hero, but this time around the portraits are actually very good. The background graphics, new city pictures, and creature graphics are excellent. Heroes of Might and Magic III sets a new benchmark for this excellent series.
The music in Heroes III is good, but it doesn't match up with the superb opera tracks of Heroes II. Who can forget the Sorceress or Warlock tracks? While my usual preference for music is along the lines of Rage against the Machine, 311, and Kid Rock, I probably would have bought the Heroes II Musical CD just to play in my CD player. Not so for Heroes III.
The largest change in gameplay terms is that there are now two heroes per city type, while as before there were only one. Each town, of which there are now 8 instead of 6, supports a fighter-oriented hero and a spellcaster-oriented hero.
The larger number of castles mean there are more troop types now, and there are huge numbers more. Everything from the lowly troglodytes to the awe-inspiring arch-angels have been added. The Heroes franchise continues to enrich itself in fantasy lore, and has fleshed out its ranks with such common creatures as Beholders, familiars, gremlins and devils as well as virtually every creature from Heroes II making a return. Also, every hero class from the original except the sorceress returns as well.
Another difference regarding creatures is that the number of lower leveled creatures produced each turn is greatly increased. This means that it is easier for a castle with only lower-leveled creatures to still mount a threat to a seventh-level creature warlord.
Another difference in Heroes III is that on the tactical level both shooters and flyers are less powerfull than before. Flyers can only fly as far as their speed allows, and shooters shoot at a penalty when their target is out of range. While both of these can be helped by a hero, it is a signficant difference from Heroes II.
The story line in the game is broken into mini-campaigns for the side of good, evil, and the neutrals in between. While it does resolve, it doesn't end. I like how NWC has integrated their two hit franchises, and hope they continue to make tons of games in both.
Thats about it for Heroes III. There aren't any real revolutionary changes or innovations, just evolutionary ones. What I would like to see in the next Heroes installment is scenarios and balancing to where you have preset nations with fully developed heroes and cities, that go to war against each other. Most of the Heroes franchise is set around building heroes and towns, and that whoever does this first wins. I would like to see some scenarios, or even a mini-campaign, where that is all done and all that is left to the player is pure tactical combat. I say balancing here because some hero types are significantly more powerful than others at the high level.
The second improvement I would like to see is the implementation of a diplomacy system. Borders can be negotiated, treaties broken and the like. All HOMM II is right now is , "Oh look, a red guy, I had better go and kill him." HOMM II covered that ground fine, and HOMM III did an excellent job of recovering it. Four installments in one strategy franchise is unprecedented, unlike the long running rpg franchises that seem to go on for ever. So, to make the next game unique, I think this would be a great factor.