Ooh this is a cool concept, and a very cute theme around it! The controls are bit difficult, specifically when trying to change the polarity of a moving magnet. It may have benefitted from some keyboard controls such as clicking the magnet to select it, then using the arrow keys or WASD to select the direction of the poles. This would have helped in puzzles where precise placement is necessary.
Additionally, changing the direction of the magnets is confusing, many times I would try to change the direction of a magnet (even a stationary one) and it just would accept the change). I couldn't find any rhyme or reason to this and it got frustrating.