Really love the concept of charting out the world!
It might just be me, but I found the enemies to be an annoyance and a distraction from the main draw of the game, especially since there doesn't appear to be a way to deal with them permanently. For me, this game probably would have been more enjoyable as a sort of laid-back puzzle adventure. (Or if you could kill / permanently pacify the enemies, that would also solve the issue.)
The use of the mouse, WASD keys, and JKLI keys made me feel like I need three hands to play this game. Perhaps having one button within reach of WASD (e.g. E or R) for playing a tune and then cycling through the different ones would have been helpful here?
Finally, I assume it was just a bug, but placing the landmarks in the dark world didn't seem to ever get the checkmark like on the light world, so it was difficult to know if I got things right there.