Looks like you installed one of the August snapshots, which don't read PDFs and there's no cr there either - so you can't choose reader application. Otherwise, you would choose it by long pressing the number of the book, which gives you a pop-up menu.
If you want all these functions, try older snapshots - March or May
(there's only the installable version for the May snapshot).
I suppose the games don't work much, at least on Hanlin - I did give them a try, but without much success