Nice puzzle mechanic! Got 49 points in my best run :-D
It could be nice to have a short tutorial in the beginning, but then again I did understand the objective after the first round so it is self-explanatory I guess.
My main comment would be that the playing board and pieces are quite small and when I resize the window it just moves the elements further apart instead of making them larger.
Other requests would be:
- an ambient sea soundtrack in the background
- saving the high score more permanently (when restarting the game)