There was a bit of a disparity between the king's gameplay and the queen's gameplay, but that only means there's lots of room to add things as difficulty ramps up! It was really fun to see how you integrated the theme and turned it into a unique gameplay experience, giving both characters a completely different playstyle. I could see this lending itself to multiplayer really easily, and that's always fun to consider, but it loses nothing by being single player.
The interactivity between the top and bottom of the screen was ingenious, and I had loads of fun figuring out the puzzles. I would advise making the queen's tiles a more contrasting color from the background, because I missed them and thought they were a tutorial graph for a second in the beginning.
Very smooth gameplay otherwise, it was very fun to play!