USUM is good in the same way that a romhack with a new UB, poipole and it's evolution, Rainbow Rocket, two minigames (Mantine Surf and the warp minigame) and a slight remix of the totems is good but I honestly can't imagine anyone buying this and liking it. Reviewers are going to like it because they got it a) for free b) they got it prerelease c) don't want to get blacklisted by Nintendo for future releases for rating it badly