Cool puzzle concept that reminds me of Flow. I really love the music in this one -- for some reason it feels crystal-y. Haha. The game didn't really explore the mechanic deeply since there were only a couple of levels, but I can see how more complex puzzles could be achieved with this concept.
One suggestion regarding the gameplay: it would probably help if there is a way to view the entire map without having to walk, since part of the gameplay involves planning the path to connect each crystal.