I had a problem.
I think this is genuinely a good game, i loved the first William and Sly and i enjoyed this one until i got too the end. In total, there are twelve keys and 20+ chests, if i'm not mistaken? That means that i couldn't get the last key for the journal pages so i couldn't finished the game. I don't want to start over particularly, as i just spent some good hours getting to where i am, so i'm slightly frustrated.