It's just the best 2D Mario now. From all the trailers, I figured the Wonder Flower segments were a bit like a Hypernova from Kirby Triple Deluxe where it was an occasional pace-shaker, but then it just slowly dawns on you that, no, there's one in pretty much EVERY major level. It keeps things fresh at all times, the twists unexpected, and even romhackifies a few of those twists into something even twistier. It is SUCH a far cry from the New series maybe having a handful of new visual setpieces, but mostly leaned on the familiarity.
Only real complaints are a few of the levels could do with a checkpoint, because you feel the handful of levels that just don't have one. Some of the later levels feel a little precise for what 2D Mario physics permit, and it'd be nicer if it was a bit more generous with retrying. Up to and including just getting rid of lives, even if in this one they're more meaningless than ever. Other than that, yeah. 2D Mario is actually so back right now.
Only real complaints are a few of the levels could do with a checkpoint, because you feel the handful of levels that just don't have one. Some of the later levels feel a little precise for what 2D Mario physics permit, and it'd be nicer if it was a bit more generous with retrying. Up to and including just getting rid of lives, even if in this one they're more meaningless than ever. Other than that, yeah. 2D Mario is actually so back right now.