You have a README which is great (maybe add a screenshot or two), but you'll need a License file as well (these are two main criteria for open source category.
Interesting concept - I like the moving monster book. It'd be good if we didn't have to switch between table and bookshelf for every single time. Maybe have it so we can carry something like up to three books between the table and bookshelf? (seems manageable). I like the sound effects too. Great use of the theme.