What Games are so good you could literally play them every day and still want more?Watch
What is so unique about this part in comparison to the predecessor and successor? did you play part 3 only?
HoMM2 takes the ideas in the first game, and expands on them massively. More towns, more units, better levels, better combat. Excellent game.
HoMM3 takes what's good about HoMM2, and adds a whole lot of other amazing stuff to it. Better graphics and music, too. Huge number of levels, towns & units.
HoMM4 was released in a hurry by its publisher, in an attempt to avoid bankruptcy. It has a few interesting new features, but is a buggy mess and crashes often.
HoMM5 was released by Ubisoft, who rescued the license from the bankrupt 3DO. Decent, first in the series to be in 3D, but cut back a lot of the stuff from 3-4.
HoMM6 is... okay, I guess. Very dumbed down, and the town conversion mechanic is awful.
HoMM7 is a buggy mess to rival 4, except without even the excuse of bankruptcy to explain the lack of support after its release.
In summary, I like this series of games a lot, but 3 has by far the most things to do in it to keep a person occupied if we're talking 'play every day and still want more'.