That's a very cool solution! In one of the videos in Mark's dev log for this game he said that, due to mixing skill and puzzle based gameplay, the original demo had issues with people trying to do puzzle sections via platforming / skill, and platforming / skill sections via puzzling, and that moving forward he would stick to puzzles much more to avoid this.
This level seems like an example where perhaps the open endedness results in that problem reocurring. I did it a similarly time sensitive way, which I posted a video of in my comment.
You have the middle block be in the up position, then switch the L gate with the magnet so that its in the way of the block's path down. Then you make the middle block fall, so it's resting on the L gate, and finally you set yourself up a bit right of the middle block, change polarities so that the magnet moves the L gate and middle block starts falling out of your way, and then time a jump across the gap really well so you can make it before the middle block hits the button and makes the left block fall on you.