Excellent old school turn-based strategy game, reminds me of Master of Magic and Age of Wonders
You play on a strategic map only, there is no tactical fights like in Master of Magic or Age of Wonders. But battle mechanics is still very deep, with no stacks (just like Civ 5), ranged units that can hit across 2 squares (again, like Civ 5), robust veterancy mechanic, a lot of upgrades, like Silver weapons or fine iron armor for your warriors, as well as a huge variety of evil spells and creatures you can summon.
A lot of reviews mention some negative points which are just not true. For example mouse controls are just fine, pretty much like they should be in a turn-based strategy game. There is no tech tree - nor they should be, it's a magical realm, there is no technical innovation going on! There is a spell research tree however. And it's not transparent - it's not supposed to be, in this department the game stays true to its MoM roots. When you conquer the city and you can't support some of the buildings you can actually turn them off for a while - you don't even need to demolish them! Just go into the city screen and click on a building icon - it'll become kind of grayed out. Diplomacy is pretty basic - again, much like in MoM or AoW. But when you consider that this game is all about some crazy evil (or not so evil, but just as crazy) mages vying for world domination you'll come to realize that this game is not really about intricate politics - it's about destroying your opponent and his evil armies! And this game provides plenty of opportunity to destroy, whilst making it combat deep, challenging, and a lot of fun! I found AI to be pretty decent as well - certainly on par with Civ 5 on Normal difficulty setting.
So all-in-all, I reckon it's a great game, especially for those folks who love traditional turn-based strategy games and used to enjoy many a night playing Master of Magic or Age of Wonders!