I agree with the statement made that Sunshine could have been made with any character. It never felt like a Mario game. it was like the second generation of Super Mario Bros. 2, just not as good. If the secret levels weren't required to advance the game, then the game would have been fine, but Nintendo had to make then required in each level, making sure that you had to play through the game a certain way. In Super Mario 64, you could finish the game after collecting a certain number of Stars, you could collect them pretty much in any order you wanted to, and you could finish the game when you had the right amount. But in Sunshine, regarless of how many Shines you needed, you had to play through each level to a certain point to finish the secret levels, other wise you couldn't finish the game. And to me that is breaking the game. It took away a certain level of individuality that allowed to finish the game at your own pace instead of following along a dictated course.
Just about every Mario game, that I am aware of, all the way back to Super Mario Bros. on the NES allowed to to skip a head and all that and completely bypass levels you didn't want to play if you didn't, but Sunshine took that away, you had to play the game a certain way or you couldn't beat it. I just don't agree with that, especially after the way the previous Mario games were presented.