Good level, a few issues.
1. The setup in these pictures
is super awkward, especially because the shy guy can walk totally off-screen and come back on. You could probably get rid of the scroll stoppers in screen 68 and 78 and replace the pit on the other side with spikes, like in the second image.
2. You can flutter back to the bumper at the end of the first sublevel and see where the tileset changed. See if you can block players from doing that. Also, not sure if it's an issue on my end, but the screen turns black for 2 frames when the tileset changes.
3. Any chance you can lower the amount of falling shy guys in the cave segment? Getting hit by them feels pretty unfair, especially near the top of the screen.
4. I feel like it might be worthwhile to add a second midring after the cave segment. It feels weird having to replay the hard part of the level if I die right at the end, and the original 6-2 has a midring similarly close to the end.
Also the random objects in the last sublevel that Lui mentioned.