Great theme and another unique victory condition make this another great adventure!
Playing with the cards is a real treat - the printed oversized cards are very nice, drawing for each results of room type, contents, etc. I really like this style of artwork as well.
Slight update to the Magic Treasure cards is nice "If you already have this, roll on the 4AD magic treasure table instead." I be applying that to all of these dungeons from here on out.
For this set I would not reommend adding in extra Bosses - you will want to meet these guys. And they go away from the deck so at that point you could sub in a card or three...
Also note that the bosses scale along with Highest Character Level to make sure you have enough challenge. My level 2 characters made is out a little beat up and mostly leveled up to 3.