Let me first say I loved your first game. This one has in most ways surpassed it. The story is captivating. The antagonists route has been heart wrenching. My only problem is with the last puzzle for his route. I know someone else has already commented, so I can see this being an issues if you release it on Steam. After I first completed the puzzle, it shattered again. I know you said that trying to find black pieces on a black mat are meant to be symbolic, but I have been working on the second round for an hour. My eyes were burning, my fingers were cramping, and my wrist was hurting from repeated click and drag motions. I finally had to save and stop for a while. When I came back to it, imagine my shock when I had to start all over. I found that if you are not very careful, pieces can drop onto the black portion around the mirror.
With the exception of that, thank you for another wonderful game.