Hi! I really enjoyed playing this game ! You've done an elegant puzzle game, congrats :)
If I might give my feedback, the only black shadow I see is the penultimate riddle which don't use the turnaround mechanics (though I found this riddle very cool). Also concerning this riddle, it was quite easy to solve by using a pen and a paper, but for player on mobile, if they are in deplacement or on the throne, you could maybe help in the level design by making a paving or something that shows the row (argh, I hope you don't think I didn't like your game or I'm criticizing it :o )
Thanks for the discovery :)
Manu