Hey, you're welcome!
I would say that rooms 35 and 45 were quite challenging, but I've managed to overcome them. Jumping the caterpillar was especially frustrating since it required very precise timing and I'm just not good at this. I wouldn't say that any particular room has made me quit, but when I reached room 34 I felt a bit overwhelmed. It's just that rooms are so mechanically dense and full of challenges, and there's little to no breathing space between them.
With that said, I can easily see a platformer puzzle person relishing your game precisely for the things that I found somewhat frustrating about it. Namely, densely interconnected puzzles and hardcore platformer challenges. I'm just happened to be not that kind of person :)
P.S.: oh, and thanks for the map! It made me realized I've missed some of the secret passages.