Nice game. The Moonlight Sonata remix was a big wtf moment for me though.
A lot of the levels had dead ends which were there just for decoration and served no purpose to solving the puzzles. I think it would be much better if the levels were designed to be much more compact, with only the parts that were important to the puzzle included, such as 3x2 or 3x3 pathway formations, or 2x2 squares. The camera could also be zoomed out a bit, you couldn't see the whole level at once, which meant possibly going somewhere only to realise it's a dead end. I also only realised at the end you could use the mouse to move the camera around.
But overall, I still enjoyed the game. Good work!