I had a WONDERFUL time playing this!
Although puzzle games aren't really my thing, but I was still amazed by the level design, especially the last level, where I had to use the magnet and activate the door from a distance, stopping the block from going up and blocking my path. I bet a lot of effort went into that one.
Also the game just feels satisfying, with the new platforming system and screen shake effects. The settings helped me a lot with remapping keys, which really enhanced my experience.
Awesome work, Mark!
(By the way, it would be nice to implement some dual-purpose design, like mentioned in earlier episodes of Developing, like, when holding the magnet, walkspeed and jumpheight is reduced. I guess this could also make some new puzzles, where the catch is that the player couldn't jump across a large gap while holding the magnet. )