Since there is the total damage done on one side of the health bar it would be nice if there was a total percent damage done based on the health bar as well
If you do add more levels you should add something that can allow you to trade your gold in dungeon for some health like and wandering medic that would be a rare pop up. And/or you could have something like a shady goblin that you would trade some of your health for some extra cash. You could also add with the higher levels two monsters at the same time with the option to pick your target. Just some ideas if you would like to use them. :P
I think the boss was just an angry dad because the king just up and stole his daughter and was like "I'm gonna steal all my grandkids since he won't let me see them" and the king was "your evil for stealing my childs!!!" (The end of story.)
Thank you, these are some great ideas :)