Code of Princess, like many Atlus games in the past, offers a couple of nice physical pre-order bonus items: a soundtrack and an artbook. Perhaps, considering the nature of Kinu Nishimura's character designs for this game, this one isn't necessarily for public display. You can see what we're talking about in the trailer.
Also visible in the trailer: information about the cooperative and competitive online multiplayer, which remains a rarity for 3DS games. Just don't watch it at work!