This. Is. Beautiful. I have some constructive feedback but I don't even care. Just looking at it is mouthwatering. Amazing. Love every inch.
In case YOU care about the feedback, I just thought it was a little difficult to tell which line the key was on in the final stage (I tried to get it on the middle layer first). The robots are clear because of their shading, but I'm not sure how you could achieve the same result for the key thing (different shades won't stand out so much when there's only one orange on screen...). Having to click the buttons also made the timings a little difficult particularly when I was lining up to switch layers, I suspect using keys or controller buttons wouldn't be so problematic, but otherwise there may need to be larger on-screen buttons?
Again, beautiful work.