Really enjoyed this game, great atmosphere and really interesting puzzles.
A couple of puzzles did cause me problems though. I couldn't do the music box puzzle, I managed to figure out that it was related to the stars and balloons, but I just couldn't get the individual notes, in the future I'd suggest using fewer pitches and also maybe include some visual information as well to help out people who are hearing impaired.
Also with the mushroom poster I was a bit confused, because the two column examples line up with the grid I originally assumed they were referring to what could be placed in rows in the grid, rather than entirely separate example columns, maybe if there was more space between them I'd have got it faster.
Overall the game was really impressive, great job.