Demo was super fun, I think everyone agrees last puzzle was probably the biggest stumper at least for a bit. Something I thought was unintuitive about the magnet was like charges not repelling, the first thing I thought for the final puzzle's solution was repelling with a like charge, but I was frustrated when that didn't work.
The throwing mechanic still feels a little weird, not quite sure where to put my finger on it though, sorry. Getting into levels by throwing the magnets just breaks the pace even if it's just for a second. I hope sound design is in the next demo, the quiet felt weird the whole time.
I can't remember which room it was, but the puzzle with the two drill bits felt weird because it was hard to tell where the magnetic field ended. If it had been more definite, I would have been able to tell my first "assumption" (as you say) wasn't the solution to the puzzle.
Overall a good demo and I'm glad controller mapping works out of the box