There is no indication that you need to go so fast with the book puzzle, to the point where I'm guessing it's a bug? That and the final puzzle were the most annoying (the latter more because while I knew generally what I had to do, the specifics of it aren't really seen in most point and click games, so it was unclear and frustrating).
The musical note puzzle was clever though, and it felt great when things finally started falling into place.