- I think it would be nice if you didn't have to walk past all the levels you'd already completed after each level. (maybe the magnet can drop out of the pipe you had thrown it in instead of the one at the start or the layout of the hub could have a better layout or more frequent checkpoints)
- Is there supposed to be sound? You said something about music but I don't seem o be hearing any.
- I like that you have to hold the reset level button for it to work but I think it would be nice if I knew how long I had been holding it already a bit better with either a progress bar or animation that was a bit more involved than just the icon growing.
- I think that the level pipes suck up your magnet regardless of which color or icon is displaying yet, it fixes this by showing the "+" icon and the negative magnet color. I think instead you could make some third symbol for both (possibly just even having it be a striped pattern using both positive and negative colors)