I quite enjoyed this level. I especially liked the catchy music and the interesting jumping challenges (for example, x996 y996 made me scratch my head for a while).
I do have a couple suggestions:
It wasn't always clear to me which way to go, and it was annoying to backtrack once I realized I didn't have the right powerup. (I ended up using God Mode to jump around the level because of this). Making it quickly obvious that a powerup is needed (like Nifflas does in The Machine) makes the level more fun.
Second, while the tilesets looked great, the environment had a feeling of sameness to it. Most really good Knytt Stories levels have a feeling of tension or mystery to them. Adding dialogue, story, and atmospheric sound can help. Also, for me, placing the setting of the level (largely) underground or inside makes everything feel a bit more surreal.
One last thing: I saw a winter version of much of the level (which was really neat!), but there didn't seem to be anything new in it. It would have been great fun to find a secret in some corner of the winter version of the level. Did I miss something?
Looking forward to your future levels!