Very cool game, challenging and smart puzzles. I'm a big fan of the Portal/Talos Principle genres and this one has an enviable gameplay mechanic as well.
My only criticism is that it can be quite frustrating handling those cubes. I would consider having them not rotate freely when you grab them? It was quite difficult to place them where you wanted when they spun around a lot. i thought the grid-style environment around you was a good idea to align things (the box your jumps etc.)
Very good effort.