A game with substance, a game with so much work put into it, so much attention to the detail, all perfectly executed.
Let's get the technical stuff out of the way. If you like tactical combat on a hex grid, along with some adventuring, questing, army building and managing, and RPG stat development, this game is as good as it gets. Straight to the point: If you are a HoM&M player you know exactly what this game plays like. If you haven't played a HoM&M game before, be prepared for a really deep tactical game that needs you to get involved with it and will reward you at every turn in ways you wouldn't even expect.
The graphics are what you see, colorful and cartoony, subject to your taste. If you like them now, you will still like them in ten years - they are not meant to be a tech demonstration. What you can't see until you have played for a few minutes is the incredible amount of detail and decoration everywhere. This really is a living world, completely full with inanimate objects, little creatures, environmental effects, all extremely rich and detailed from the tiniest island to the biggest (well not that big) continent. Everything that is not beautifully animated, is lovingly drawn and painted. Every menu, every window, every different creature and every type of landscape looks like art.
The sound is mainly various fitting musical arrangements and typical sound effects. Nothing special here, a beautiful score that you can always turn off if you don't like.
The story. Typical fantasy story, you go to another world to retrieve a mythical hero (actually the hero from the first game). Again what you won't see at first sight is the depth and the detail. First of all, while the story backbone is typical, the delivery is anything but. The sense of humor will catch you off guard and often leave you smiling when you thought you were about to read a typical quest description. Again, there is so much detail, so much (optional) text that is there purely to flesh out the world. There are dialog choices purely for choice's sake, and of course choices that affect the outcome of quests. There is flavor text everywhere, on every creatures and every object, every little icon and every doodad in the world. And there there are the numerous but cleverly subtle pop culture references.
This attention to the detail is all over the core game it self as well. "Creature features" as the game calls them, hundreds of abilities and dozens of interactions make army composition a game on its own, equally deep as building a CCG deck. Scrounging for troops at the first few levels, you will quickly find yourself making complex strategic evaluations and choices before you even step into the battlefield. Then of course you have the dozens of spells that you can acquire, and all of that is bound together by the specialization/talent system making it even deeper.
You don't have to minmax everything to win either; reasonable thought is required - because you can always fail if you ignore the basics - but there is still plenty of room to play in any number of ways you like. And you will play, again and again, because there is simply so much offered here. The technical stuff is also well executed, and the same attention to the detail is found here as in the rest of the game. You have all the audio and video options you could want, the game even supports 3D if you want to put on your cyan-red glasses. More importantly, the save function is superb. You have an autosave at area transitions, a different kind of autosave at certain storyline events such as visiting castles, a normal save feature, and three quicksaves - this means that you can quicksave three times before your last quicksave is overwritten. You probably won't need all that, but if you do it will be there. Of course, saving is instant.
I guess this will have to do, if i haven't got my message across by now i can't do it any better. This is a rare kind of game. It is a game done just right at every point, a game that will immerse you completely into its lovingly crafted world and live up to your every expectation. Not trying to impress or convince anyone, it just lays a living gamescape there for you to experience. I wholeheartedly invite you to do so.