NOTE: Moving onward from level 17 there seem to be no more levels. I suspect that level 16 is just the last level? Good concept, I think that with very few mechanics this was interesting. Perhaps some harder puzzles would be interesting..?
Level 16 behaved "strangly".
I.e. when reloading it moved onto "level 17" which was just an empty level, after going back and finishing the level, nothing happened..
^
covered up any spoilers
EDIT: also sometimes when restarting the level this sphere..
.. doesn't move when commanded to move forward.