This idea just makes me grin all on its own.
I have a high resolution screen so I found the tutorial text very small, but once I had read all the information, the game had a great flow to it. Not too much to manage so it never felt stressful, but enough to be engaging and satisfying when on top of everything. I love the feel, the heroes played smoothly and the idea of reviving the boss especially had me laughing.
My final hero got stuck trying to open the final chest. I picked up the chest and replaced it, I took the chest out the room and a new one in, but he seemed to be locked onto that one chest and never managed to open it. So sadly I don't know if I missed something at the end.
But honestly this is an idea with legs. You could add loads of character to it, like custom dialogue throughout, make the heroes respond to their own experience etc. Hell, maybe it would become something where they leave reviews and your dungeon business expands!