It might be helpful to add to instructions that the ball stays in same spot if moving would cause it to go off the edge. I play a lot of games where the board wraps around (e.g. moving left on left edge moves to right edge), so this took me a while to realize.
Got a little frustrated during the first part, but the second part brought it home for me. Really incredible concept that's much deeper than just a game. 5/5
Finally won for the first time with a single corner of heart left! But I will definitely keep playing just because it's so much fun. Absolutely incredible concept! 5/5
When you're too close to the edge of the square on the walk the sequence levels--so frustrating! Nonetheless, awesome game; great puzzles, design, and story. 5/5
Thanks to @SwashBlade for explaining why an undo button wouldn't work; that was going to be my main critique. However, I think a "delete piece" option would be very helpful; it's kind of frustrating to reset the entire puzzle when I know I only place the last piece incorrectly. Or, perhaps in keeping with the drag-drop interface, an option to drag a blank square over any space; if you drag it on top of a reflector, it removes it from the board and places it back in your inventory. Still, nice overall; 4/5
I'm just thankful it doesn't display number of moves, or I'd be embarrassed. But, you know a game is good when you're horrible at it but still want to keep playing ;) 5/5
Also, would be nice if your score were only adjusted if it is HIGHER than what you have on a level; it's not very fun to have a penalty for trying again.