From having played all of the games in the Heroes of Might and Magic series, I would describe the first and the second as being much closer to each other than the games that came later. Heroes of Might and Magic II was basically the first game with better graphics and tweaks to game play. I don't think it would be incorrect to describe the first Heroes of Might and Magic as almost a beta release, with the second being the polished project. So what then does a game company do after they have released a good turn-based strategy game one year and a classic game of the genre the next? While there wasn't much to be done to make the underlying game play better, there was still some sparkle and shine to be added.
Heroes of Might and Magic II:The Price of Loyalty was released in 1997, and kept almost all the basic game rules, graphics and units in place. It did present some new features, such as new artifacts (including some that had both positive and negative effects), new structures (such as jails, where you could get a free hero), and stables, that would give you a week of rapid movement). It also included over a dozen new maps, many of which stretched the boundaries of the first game, as well as four new campaigns, that were much more difficult than the original games campaigns.
The campaigns themselves present mostly interesting strategic puzzles, although one has a final battle that is too boring to be worth its difficulty, one is so challenging I have yet to beat it, and the other two have final battles that are very long but almost always winnable.
The few new elements that the game designers added perhaps gave the game a little more depth and width, enough to ressurect a player's interest in the game again. Since the original game could be challenging and intriguing for months or a year, the expanstion pack was good for another month or two of interesting game play, at least.