Yeah, thanks for playing it anyway!
As for the mouse being locked, it's the main problem that I'm trying to solve at the moment, as Unity's cursor management is a bit weird. I could change the key to open the library to use E instead of the mouse click, but that would be weird too. So for now you need to use the keys, it's right.
About the second thing: yes, having the library inside the game would be way more accessible, but as you noticed it would be a big copyright problem, as I for sure couldn't have any kind of permissions.
To end this long enough reply, thank you again for the interest!