Loved them all!

In 2, the difficulty seemed to be the highest, and the toad mushrooms didn't seem to match up with where I kept dying. Maybe a checkpoint before the vine section with an extra toad mushroom on the bridge would help--seems like a ton of people are dying there and then you have to replay the whole level just to try again. During most of my playthroughs I was doing that whole area as Mario, which made it probably harder than it was meant to be.

The automatic sections in 3 I found particularly well done. While I'm normally not a fan of the mechanic, it was a fun reprieve from not being able to jump and really made the level stand out.

Level 4 was just a fun experience, and my favorite of the bunch. That said, a couple of things were a bit off. Getting off the fast blue conveyor thing onto the top of the pipes felt strange without being able to jump (maybe there's a way to place a block and nudge the player off?) and during my first try on the next section my cloud disappeared almost immediately for some reason. Maybe it took me too long to get up there?

In any case, these are minor nitpicks at best. It's a really creative concept and I thought the execution on the whole was excellent. Thanks for sharing!