I beat Mario Wonder, well at least Bowser's castle. I still have the secret world and a decent # of ? Levels thatve now appeared on my list of stages. I like that. You beat the game, the game tells you what levels you're still missing. It'll be fun cleaning up the collectibles and revisiting levels.
The variety in this game is incredible, where I rarely saw the same idea used twice. Nintendo could've easily included 2x as many levels by simply using more of the same ideas but iterating them differently. Replaying levels is less of a slog compared to a lot of previous 2D Mario's because there's a much greater sense of uniqueness in each stage. Of course, there are SOME repeated ideas, it's not like every course is totally unique. But as a lifelong 2D Mario fan, I am impressed.
The drill cap, the elephant, and the bubble flower are all fun. Those, with the badges added in, plus all the environmental tools the game throws at you, stay fresh the whole way through. Nintendo crafted an exceptional platformer.