I don't have much to say (but I am someone who thinks that then ends up writing an essay-like comment), but I do want to put forth my thoughts.
Fresh in my mind right now is the "last level" (the level closest to the "exit" or number locked door): this sumped me. I felt like I breezed through all the others (such that I only remember at least one other). I had to "see" how others solved it. I saw the problem but just could not see a good solution. I kept wanting to throw my magnet friend to hit the switch. Then I tried to race gravity. I saw a possibility of using Mag-Friend to block big blue/negative block from hitting to button (and later noticed that someone else did exactly that), but that felt like that was cruel to Mag-Friend and not what you intended. As I skimmed this comment section, I did find a comment that pointed to a better solution of using the swing door.
My "block" of text above shows that the last level seems like a significant step up from the others. I don't know how or why, but I feel that there were no connective lessons from the previous level(s) that adequately prepared me for that last one.
While the hub idea is a good concept, gating the player at critical points helps ensure you, the designer, know the player has the base of skills and knowledge needed to do "the thing." Baba is You does this well (in its cruel way).
Another thing that struck me was the nature of the relationship between the player and Mag-Friend. Especially with the levels just ending once you got the key, I felt I was using Mag-Friend as if they did not have a face. I don't have any solutions except some story reasons that justify that relationship dynamic. (Or I'm overthinking all that in some way.)
Otherwise, the visuals are clean and clear about what is going on. I was not too fond of the parallax effect in the hub. ... Other than that; I like the style you got here.
As I thought I would, I made an essay of a comment. Thank you for reading this, and I hope it helps.
PS: I should mention that I exclusively used my Xbox One controller to play the game. I did not feel the need to change any of the settings.