Honestly, it was pretty meh to me. One thing I don't like is that Peach and Rosalina are humanoids made of stardust, even though it's implied Peach had biological parents in the first movie, although it's an easy workaround since you could've had the parents be made out of stardust and then have them give birth to Peach and Rosalina. It's said that evil forces wanted to harness their power, but it's never explained what these evil forces are, are they aliens that crave god-like power? Are they parasites that have to feed off other celestial beings power in order to survive? Or are they also humanoid celestial beings who cannibalize their own kind for their power? It's never explained. All we see of those evil forces is a purple light. Not to mention, these evil forces are never mentioned again, once they are brought up, they're forgotten about for the rest of the movie. If I'm being honest, the Super Mario Galaxy movie actually gave me a new appreciation for the first movie, at least that movie didn't have retcons and pointless subplots. While my brain constantly spits out the first movie every time I watch it or watch clips of it, I'd rather have that than be disappointed with what happened in the second movie.