Your developer series has reignited my interest in Unity, and the fact that you made this prototype is really inspiring. The prototype itself plays really nice. I played with mouse and keyboard and everything just felt so smooth and intuitive. What little tutorial you presented was all I needed to figure out the mechanics.
If I had one issue, it would be that I solved some (but not all) of the puzzles more by just trying a bunch of things until something worked than by getting the "Eureka" moment of seeing the big picture. But obviously that's a very high standard to meet and I think you've done a great job building this game so far!