I really like the game, but the infinit heal in stage 7-11 is just annoying and bad level design, at least in my opinion.
You need a spezific healbock skill or get all the struggle and have to target the crystals (which messes up my party ai). I have no problem having challenging level which need certain skills, but then give us the needed ressources to level up new mons. But the vampire set is only available after the level so i can not get a farmer.
Even the level 60 fire friend is not able to kill the boss
My suggestions would be to give the vampireset earlier, spawn just a limit number of healing crystals or make them stationary similar to the bull or dragon stage.