Finished the demo, although only 80% completion. I noticed that books aren't saved within a same run so every time you exit and continue your run you have to recollect everything.
Oh that’s weird. Seems to be something to do with how the built versions of the game are saving the collected books. Would have never spotted that, thanks for letting me know!
This is now fixed. Turns out it was a known Godot issue: I was using the new resource UIDs to save references to the books you’ve collected, but resource UIDs don’t work after compilation ¯_(ツ)_/¯
