Dark Heaven Apocalypse is by far my favourite game, I rarely play my others and have no plans to buy anymore games. It is a very simple to understand game with straightforward rules and is easy to learn, even for beginners. You can use any miniatures in you collection, there is an effective point system for making any troop type at all. For instance, you start off with a basic race such as elf or medium sized monster, then buy options like using a two handed weapon, being a hero, having magic spells or being a vampire, to name a few. I can't think of a fantasy miniature off the top of my head that you couldn't easily use in DHA.
Once you've assembled your army it's time to play. Each figure has a class, from 1 to 4, that mostly depends on its armour type, with the lighter armour types moving first, in the movement phase of their class, starting with class 1. You alternate moving all of your class 1's, then your opponents (you can have as many different sides as you like) move all their class 1's, with the armies with higher initiative rolls moving first. Then you move on to your class 2's, etc. This makes sure that even in the biggest games you'll have something to do often instead of waiting an hour for your turn like in some games.
The magic system in DHA is just as easy as the rest of the game. The spells aren't too powerful but are very useful in the right hands. The melee system is also a thing of beauty. You group all melee combatants into various groups then choose a figure from each army in each combat to base the roll off. You roll, add your modifiers and so does your opponent, then remove causalties. It usually only takes one roll, but you keep rolling until no sides figures are touching those of an opposing side. This speeds the game up considerably, making 500 figure battles possible in one session. It's great.
The game is great for big battles but you can do smaller battles too. When I first started my armies had about 20 figures in them, and we still had great battles. If you have small armies you can also "power up" them by making each figure worth a lot of points: the battles still the same size but instead of being a regular small skirmish its now a battle between mighty heroes.
Ok, no game is perfect and neither is DHA. Some people may find the rules too simple, so if you want a complex game with very long turns then DHA isn't for you. The book also doesn't contain rules for magic items, only the heroes listed can use them. The rules are promised in a future supplement, but thats another problem: DHA has been out for several years and has no published support at all except for "Casket Works", the catalog/magazie of Reaper. This is unfourtunate, because it is such a great game. I hope you'll check it out.