2010-12-17 (updated 2011-02-08)
I'd claim this is Dungeon Keeper 3 if I didn't know better.

A vague cross over of Dungeon Keeper 2, Overlord, and some obscure tower defense where you yourself need to kill all the foes personally.

Perhaps best way to describe Dungeons is that it's a Theme Park of Evil where everyone who is enjoying themselves (too much) or is trying to leave gets killed. Everything you build is to entertain the heroes while making sure they die before they leave or are completely satisfied (in which case some heroes just use town portal spell and disappear before you can intercept their escape).