Contrary to expectations, it's rare that a GBS game really captures the Game Boy soul, especially of a proper adventure. This game manages to do that from the get go. I did find some humor in its demo state, like the sage telling me how useful the book is and the protagonist is just like "nice, happy for you".
The sunset scene is a banger. This would be a choice use case for GBS's tile animation IMO (which I saw used in the water, also a great use).
The music puzzle was pretty fun. It took me a sec to realize it was one because I was thinking about the sound effect and how GBS should bundle its own solution for them, before I realized it was a "wrong" buzzer. Soundtrack overall enhanced the world, with a feel like Pokemon Red/Blue.
I almost gave up vs the Pegasus Knight, but they ragebaited me enough to stick with it. Then after I won, they stood on same tile as me to prevent me from moving. (I got out using the pause menu)
Feature request: let us pet the dog.