I'm really happy to here you say that!!! I am a huge fan of Celeste and definitely took some inspiration from it, and I took a long time to make the physics just right. I'm also really glad you liked the hair physics they were difficult to make but I think they were worth it!!
About the level with the deflecting platforms, I definitely should have given them tutorial they do need some explanation, basically if yo make yourself big you can run fast but cant jump high, likewise when your small you can jump high but cant run fast. so what you have to do is turn yourself big, run up to the edge and then shirk yourself until you become tiny as your jumping, to preserve your momentum and launch yorself to the end.
Also I played your brothers game and its absolutely great, I already left a comment on his page about it but its definitely the best game I've seen all jam