First of all, congratulations on finishing a game, and you did a great job on what you have accomplished! I really like the dark/gothic fantasy atmosphere and style of your game. Also, claw wizard - brilliant!
I had a few runs and here's what I thought of gameplay and balance.
The first run I tried to explore everywhere and bought the first upgrades that were presented to me. I found I ran out of gold very quickly and so many rooms presented upgrades I was unable to obtain. This was a little bit frustrating as not many rooms contained gold. I died about half way up when the difficulty of the monsters increased and I didn't know the best way to beat them.
The second run I also explored everywhere but this time was more selective in the upgrades I chose, which helped, but I still struggled when the claw wizard absolutely destroyed me. It seemed to do quite a lot of damage, however, maybe I wasn't paying attention to my hp as I was focusing on trying to sap it's mana.
The last run I mainly headed up the tower as quickly as possible only stopping the at rooms on the way or visible from the stairs. This time I got all the way to the top to face the tyrant but struggled to defeat him before dying as I had no way to heal myself.
Hopefully that will give you some insight into how a player might approach the game. I wouldn't want to comment that the game was too hard as I feel like this is probably intentional, and to make the player make conscious choices about which skills to increase and which resources to use including mana.
One suggestion I would make is to make items available in combat, as this would allow a player to have at least 1 way of healing during battle. I think on one of my earlier runs I had a hp sap type spell but this was offset easily by the damage the enemy would inflict on that turn, making it less effective as a healing tool.
Some of the skills had more obvious uses that others, for example, strength, toughness and arcana have obvious benefits to combats and traps. I felt dexterity only had a use for traps, which I could use something else to overcome. I didn't see any use for faith so it was unclear what this would affect. Other than more damage, I think having some more feedback that the elemental spells were more effective would be helpful.
All in all I think you have a very good base, and I'm really impressed with the progress you've made in the bootcamp with this. I think there's a lot of room to build upon what you have already to make this even more great!