I wish the screen size were a little better but this is really done exceptionally well. The rotating mechanic is very smooth, the dragging is very smooth, the picture quality remains high, the animation is smooth, and the snapping works really well. Overall this is just well coded and is fun to play. The one thing I would recommend is increasing the screen size, making more of the screen space part of the puzzle rather than having all the menu stuff, and maybe giving more space in general to put loose pieces.
Other than that this is really cool.