Hurt Me plenty.
I don't know if it matters, but I failed the tombstone puzzle by stepping on the wrong tombstone accidentally, and it said 'nothing happens' and I noticed that the max monsters in the map went up by 1. (I was at 59/60, then it turned into 59/61)
EDIT: Whoops, I was using skulltag. I guess it doesn't work with skulltag.
EDIT AGAIN: It still doesn't seem to work. Is the level supposed to end once you kill all the enemies?