Hey guys. I played more and got two bugs. First: when I drop a book at doors, it falls on the other side of these doors. Second: when I load the game, sometimes my stuff disappears, and I cannot get these things anymore. Both of these bugs you can see after 16:00 ( 16th minute) on my second video. I will replay the game again because I cannot finish it now. I cannot get the green book anymore at all.
Thank you for playing again!
Dropping items close to walls or other objects makes them go through them, I'm aware of that but I don't really have a solution in mind yet. As for the the second problem you mentioned, it's not a bug, there are few checkpoints in the game so the game sent you to the last one you activated, but yes, the save and load system is still far from perfect, those numbers appearing above the red book is definitely a bug.
Adding to that, even though you lost the green book it still doesn't break the game, you could still reach all of the three endings, let me give you a tip, there were a few things you missed in the game, mainly in the library and in the labyrinth, also, the blue key can be used differently.