Hi Mark,
Great Demo.
I think the game looks good.
The character overall feels pretty good to control. The magnets throw and changing feature works pretty well too but it did feel clunky at times.
I also noticed that some inputs don't respond very well. The restart button stood out as needing two presses most times.
Speaking of reset I noticed that there was a number of levels where you could get yourself stuck quite easily and have to reset in order to try again. This feels counter intuitive as the levels are puzzles asking you to take in all the elements and try different solutions. I understand this is probably due to these being test levels but its something to keep in mind.
Other than that I really enjoyed playing your game and look forward to seeing what you do in the future.
Thanks,