A simple idea, nicely executed. My only complaints are regarding clarity of game elements.
For example, the fact that green blocks can only move on 1 axis is not immediately obvious and I just assumed that they were a regular block but in a different colour. I assumed that when they refused to move along a different axis, it was just a bug.
Maybe a better way to explain this would have been to have a level with two green blocks, and two buttons, placed in such a way that it's impossible to use each block for the wrong button. That way it clearly demonstrates that these blocks can only move along that axis.
I also would have liked some sort of visual indication of which leg was pinned to the floor. Perhaps a smaller circle inside it.
Overall, I had fun playing. Great entry!
