Very nice game, great feel and cool levels.
Some things to note:
One, with the doors the open switch sides when you get close, if you the instantly change your direction, the gate doesn't register that and you need to go back and then return for it to work.
Two, in levels 5 and 6, if you get stuck, by falling to a hole or just opening the screws in a different order, you can't easily go back and you have to restart and do the whole thing again, which feels bad.
Three, if you could make the range from which you can pick up the magnet bigger, and increase the speed of the character in the hub(maybe add a sprint mechanic, it feels horrible to open the wrong level and having to walk in all again), I thing it will greatly improve the feel of the game.
Waiting to see how the game will evolve!