I see what you mean - I absolutely should have mapped space bar to jump instead of menu, though I did not think of it at the time.
I thought the same thing about the end-of-level solution replay; it was 100% unintentional coincidence that it happened, and yet it worked out so well! XD
And you're right - I should have used the sword mechanic more; I was thinking of it more as a way to redo some of the chaos when you mess up too badly, but it could surely be used as a way to solve a puzzle, too.
Thanks for the detailed comments!