Thank you for playing and I'm happy to hear you continued on and made it all the way to the hall of mirrors!
I agree with all your feedback. If I were to redesign parts of the game I'd make the player automatically move to the next level to avoid accidentally entering the level you just beat and also add a button to get back to level select. I would also redesign level 2 a bit more to introduce momentum conservation in a clearer way and add an additional section to demonstrate how to stack the player on a statue without a failure state.