What a wonderful game you made! With its nice music and SFX, it makes for a nice and chilling puzzle game (I just turned off the ambience sound, it was driving me crazy).
I also liked the tutorial screen, but it was a bit hard to tell the difference between the tutorial parts and the clickable controls. I also thought the hard mode would be a somewhat different puzzle, it could be interesting to indicate the difference between the two modes on the selection screen.
I'm also fond of the popping animation and the recursive search. The puzzle itself was great, not too easy nor impossibly hard. And I really reaaaaally love the art and the story (stories?), it really gives soul to the game. Congrats!