Try to keep your treasure for as long as possible in this game of dungeon building. Waves of heroes come during the night. Take control of units you've spawned and try to hold them off. Place traps and create new sections of dungeon during the day to repel the heroes with even greater force!
Some details since I didn't have time to implement a tutorial:
Basic - Nothing special, but you can upgrade it to add more traps.
Captive Princess - Increases attractiveness of surrounding rooms (which attracts heroes to those rooms).
Torture Chamber - Increases amount of souls gained by heroes who die in this room.
Mausoleum - Spawns skeleton mages.
Orc Breeding Grounds - Spawns orcs.
Treasure Chamber - Moves your treasure chamber to this one. Replaces the old treasure chamber with a basic room.
That's about the only thing that I think is totally obscure the first time you play. Everything else can probably be figured out with a bit of trial and error and paying attention to the info box in the top right corner.