A Really Good Concept...
There were some frustrating aspects about the game, like when you get pigeon-holed into taking gradual damage over the course of the maps, then wind up in a situation where you have 5 HP left and the key is literally surrounded by Mandrakes (after the 20th attempt at taking no damage in this sort of scenario, one develops a sour disposition toward the game itself).
I also feel that there should be an undo or reset function of some kind in the game that allows you to make a few mistakes (maybe give someone 5 undo's the entire game or something). Hell, I'd make that into an item, as there's no sense in giving it for free.
I also had a few minor nags with some of the enemy attacks. A few times I wound up in a situation where I could be hit by enemies with indefinite range (Beholders, mostly) right off the bat and had no alternative but to flip the board to try and get out of its path, but would get hit in doing so. This, coupled with the annoyance that I discussed above about the game dwindling my health down can make for a series of needless deaths. It didn't affect my experience too much, but perhaps the random generation function could be altered so that an enemy can't attack within a certain number of turns, or maybe make it so the map can't generate a combat situation right off the bat.
I also felt the armor didn't scale very well with the damage. After getting hit for 8 - 10 damage a pop, I go and purchase the armor. However, the next stage has enemies that begin hitting me for 8 - 10 damage as well, with some hitting for even more than the previous stage's enemies after the armor upgrade. Makes the armor feel less like an upgrade and more of a tourniquet.
Again I love the game and the concept. These are just some minor gripes I had with it.
Perhaps for the sequel, you could incorporate movement upgrades or different weapons that allow a variety of attack paths. Just a thought.
Thanks for the great game!