I rated 5 this game because I found it to be an excellent piece of playable-IF to solve. A mind-bending puzzle that captures the player without a sense of frustration. Overall, it shouldn't take too long to complete it.
Since the very beginning of play you "sense" that something is strange ... that sensation kept me going ahead without frustration even though I moved around in circles for quite a while, but I knew that somehow I was on the right track. Then ... it "clicked" to me and everything was clear. Nevertheless, once the core of the puzzle is grasped it still takes some strategic moves to actually solve it.
No distractions, just a polished and well presented puzzle with all its elements in plain sight. Nice atmosphere.
Surely one of its own kind -- I don't recall coming across any similar puzzles.