The come glide with me ones were the most difficult in my experience. I've never had the best experience with fan/wind based platforming in games. What was the most difficult for you?
All of them are easy imo. Bubsy 3D as a whole is as easy-going as a Kirby game to me. The gliding bonus rounds are my favorites, love the feeling of flying around in a big space.
Rarely got to see those bonus levels as I didn't usually get the 150 atoms needed to unlock them but nice to see them all! Also curious you say in the description the bonus levels have official names in the manual but they don't appear in the manual of my copy (I have the European version so maybe that's why?)