Okay, so I beat the main game.
-Bowser has a fantasy dragon that isn't cartoony at all and looks like it came straight out of Fire Emblem.
-Mario and Peach almost kiss but then they don't. Seems to lend a lot of credence to the "Luigi marries Peach and Mario marries Pauline" theory.
-Yoshi confirmed.
-Some of the postgame stuff is really hard. I'm working on a 2D segment that borders on kaizo levels of unforgiving places unless I'm doing it wrong somehow. This is not a bad thing.