The layout, art, and presentation are all praiseworthy. The contents inside are very imaginative and eventually reminded me of The Dark of Hotsprings Island once I realized what I was really reading!
For some reason on my first readthrough I thought that I was missing something in regard to context and I imagine I might not be the only one. It's clear on reflection that this broader location is of course a sandbox and not an "adventure" in and of itself, straight line or not. My only real feedback is that even a small bit of direct-to-reader introduction might help to clarify what this Z-Fold is really for. As it stands it presents a lot of nouns and exposition that on first read are difficult to parse - "...The Regent is actually The Prince in old age, sent back in time to feed The Prince thereby..."
Full marks all over so don't get me wrong I just realized how I began with the wrong expectations the first go around!