Cardboard aesthetic + 3D + museum + photography puzzles + that Dark Souls-ish theme with the harp and flute all combine to create a very unique and engaging atmosphere. Great job!
I also had some issues with Aya and had to go back and take several pictures two or three times before getting one that matched. Also, the sensivity was very high by default. Actually, this was like the third time I tried playing, heh. I know you've been working on an update but I wanted to try one last time tonight and fortunately I was able to beat the game.
As an aside, I like how some of the photos that you take show up in the frames around the museum.