cryptonite is found in the hotel (the door from right of your house), you need to deactivate the door lock, the door lock can be deactivated in the garage by flipping the switch. After you go up to the last floor you will see a bunch of trees, cryptonite is in one of them.
i managed to figure the cryptonite thing, but still thx. I was actually looking for inspo bc im making a monster girl themed rpg maker game rn too lol, this was for sure a unique experience😭
