So first off, great job finishing something this large. I like the general aesthetic of the game. It brings me back to playing flash games as a kid. Your take on the theme is pretty good too. I didn't encounter any technical issues and the physics felt good enough for a jam game.
I think one lesson you need to learn is that it's easier to design a hard game than an easy one. You have a lot of teeny tiny platforms, fast moving obstacles, tight spaces, and leaps of faith. The frustration from dying to a challenge that feels cheap is greater than the joy of overcoming it.