Awesome mechanic idea! The assets and layout look great and gameplay is super interesting trying to figure out the right path. I did have two things for feedback: this is just a smaller, nit-picky one but I kept accidentally letting go of shift and I think it may help to make the 'dimension shift' key be a toggle rather than being held down. The second thing was that I felt like I had trouble when going behind walls, because I couldn't judge how far I was. I get that this is obviously part of the challenge, but at one point I had shifted so I was just a tinnnnny bit off of the coin since I couldn't see behind the wall and I had to use an extra shift to get into position.
Fantastic work! Really enjoyed it :)