After a bit of experimenting i believe the lack of something meaningful to hit that takes 1 heart is a real problem mid (5-10) game.
You have to push to find the minotaurs/chests/gnome but you end up in a situation where you hit a 6 with 7 hearts or a 5 with 6 hearts.
225 score 3 stamps might be just to much luck to be a fun chalange 🤔