Based on another player's comment, I don't think I used the intended solution to beat the last puzzle. I threw the magnet down in the pit preventing the large blue block from being able to push the button when dropped.
Might also help to have the levels numbered so you could refer to them without describing them.
Also, as others have said, for the finished product it would be great to avoid situations where you can easily get soft locked and forced to reset the level.