How do you unlock all of those bonus mini comic strips that tells of the back story regarding Nico's past? On sites like GameFAQs they say you just have to finish the game to unlock them but I've just finished the game and I was only able to unlock three of them. And as far as I can tell I unlocked those three by doing some random actions that results in a goat's "baah!" sound effect, one of which was at the Carchon's library when I kept looking at the books on the shelves.
I found the below info from a 2010 post made by 'PLASTICA-MAN' at "forums.gametrailers.com", which will trigger that goat sound;