This started out intriguing, but now I'm halfway through exploring the second level and already starting to get REALLY bored with it. It's like a rougelike without random maps where enemies stay completely still and you have no way to interact with the game other than hitting monsters, casting healing/damage spells, and throwing switches. The game is ridiculously easy on normal and I can't imagine dying in this game. Higher difficulty levels simply inflate monster stats; I guess you'd have a higher chance of actually dying, but I couldn't see wanting to start the game over several times considering how massive the dungeon levels are and how little there is to do outside of combat.
You find little story scenes here and there, but I don't think it's enough to keep anyone going. Other than that, the game seems just to be running around in a maze to find combats to level up so that you can continue to run in the maze and enter more combats. For this to work it would need a really interesting and tactical combat system but it's far too simple to hold my attention for two dungeon levels, never mind 19+!
It's too bad as the artwork and atmosphere are both fantastic. It's a good foundation on which to build something interesting, but it's just not interesting enough. I might finish up the second level before I decide for sure, but I can't imagine myself exploring another 17 of these massive dungeon levels, unless something changes radically from that point.