So I just got the mega stone shop in Rumble World as a Rank 28, but all the pages I've seen say that I have to be at rank 33. Just wanted to point out that rank 33 isn't as much of a requirement as actually completing the challenge that is supposed to be unlocked at that rank, because you can unlock it after couple of days without reaching the rank itself. One could unlock all challenges before that and wait a day and unlock it at the rank for the previous challenge. Just wanted to point that out.