Great game, absolutely love the concept. Some constructive feedback:
The options menu needs a clickable back button to exit, there's currently no visual to show how to leave the menu, and using the mouse to enter and a keyboard to leave isn't the most intuitive system.
Obviously, this is a demo, but would be nice to have fullscreen as an option in the window itself instead of just the starting menu.
Unsure if it's designed for future level development, but why not have the magnet auto-pick up when the player moves over it? having to click every time seems more tedious than anything.
Levels 1/2 maybe switched around positions? I think 2 has a simpler concept.
I love the player animations, (A old school robot who isn't affected by the magnets is very good. Could play with the idea of the magnets getting stuck or messing with its circuitry)
I think the jump reach feels wrong because the height of the level can make it feel like the player should be jumping higher, maybe increase the size of everything and zoom the camera in a little bit, this could help remove that aspect.
I would suggest a button for the user to call back the magnet, it can be tedious to go and find the magnet again if you have moved around the level. when the user presses 'c' for example, the magnet could fly back to the user.
Overall a great game demo, far more fleshed out than some demos I have played and with a very exciting concept, can't wait to see the next iteration