I really like the concept and it's well put together. There are a few issues with controls that had issues though. The magnet felt inconsistent. Sometimes the magnet pulled strong, other times it pulled weakly and I couldn't figure out the reason. If there was a power level the got depleated or it was split between objects on the level I couldn't tell; perhaps some player feed back could help.
I'm going to admit I only made it past the first level, early in the second level I I got stuck at the second spike cannon. I noticed that at the beginning of the first and second levels there was a tight difficult part right at the beginning, it may makes sense to put that tighter place later in the level once the user is used to the mechanics in place.