My only major feedback is that my instincts are all wrong for the throwing mechanic. I kept wanting to hit the left mouse button to throw instead of releasing the throw button. I do like how you can just drop the magnet though with a single button. Opening the doors by throwing the magnet up into the pipes struck me as a bit of an odd choice as well. Using the interact button would have been more intuitive I'd think. Overall though it was a nice clean demo and I didn't have any major issues with the gameplay. Well done