It is somehow the little brother of Dungeon Keeper (which I loved very much back then). So I'm happy that I found this game which is quite similar and runs on modern machines (which my copy of DK doesn't :( ).
I'm recently playing on "normal" and it is at times quite challenging. That's O.K. to make you learn which skills are most important to develop. Controls are a bit confusing at first, but you get used to it (e.g. for teleporting you have to slightly tap the right mouse button, when you press it, you get the character/squad menu).
For me, there is no reason to not recommend it. If you are not sure - get it on sale or via humble bundle (like I did).
I'm only playing single player, so I can't say anything about multiplayer (yet).