I finally got a perfect run: A full-clear with 13 hearts leftover at the end!
That can only happen if you do not use any health refills until you've looted all treasure chests, picked up the gnome, and killed the Mine King and cleared out all mines.
It took many attempts, and more than a few... educated guesses? You'll need to take some risks to do this, but usually just inferring which squares are most likely to be chests without actually seeing the minotaurs.
I finally did the same. My advice for anyone else who tries: make sure you know all of the patterns, and pay close attention to the number of remaining monsters of each type. In my run, I was just barely able to find the gnome in time (0 remaining hearts and not enough XP to level), by realizing I had accounted for all of the odd-number-power monsters except for the guardians, so a 7 clue next to an even-numbered clue let me safely open the overlap.
