Bruv...did you say you're using arrows to move!?! LMAO!!!
I don't even play MKB but I know WASD ! That's 1st day on a computer, basic gamer knowledge, chief. Maybe figure out how to use the controls before you muster up the gall to criticize them.
GMTK has entire YouTube videos about this game and he addresses many of the problems. He wanted to do a platformer, but it just wasn’t right. Many of the issues you mentioned were issues for him too, and sometimes there not issues at all. The reason the magnet door flips up when the magnet hits it is its momentum flips the door, and if this sounds unrealistic, that’s because it is. Really any mechanic that doesn’t influence gameplay isn’t really important, and one that do get prioritized.