Great take on the theme. The movement mechanic is ingenious. I also like the twists you introduced like the mirror. Level design was also good. Especially how you introduce new mechanics.
The level of polish is also godly. The minimalist color theme is relaxing. And so is the jazz.
The only thing I did not like is the forced level selection menu upo completion of a level. It breaks the flow. Getting to the next level after completing the current one should either be automatic or a one button affair that doesn't involve the mouse.
My own game also limits player movement, though not in such an elegant way.
This is a perfect 20 for me. Great job and looking forward to how you expand on this.