Really unique, minimal puzzle with nice atmosphere.
I did feel kind of lost, trying to randomly discover knots. I thought it would take me through a gradually more difficult knots to try rather than being open ended.
I also was confused by the empty hexes in the middle -- I thought maybe I couldn't click there. It might be interesting to make that part of the challenge. Either have bonus hexes or null hexes you have to work around.
Nice job!