Nice work! I like the particle fx to spice it up. The click sound felt a little weird to me, but then reversing it for undo was nice (though it seemed like undo could easily get into a state where my only option was to click was I had just undone.) I love the main image, it would have been super cool to have something like the actual 3d scene as the background but dim so it's more interesting than the flat 2d background, but then light up when you complete the puzzle. Great job!