Ever open a pack of baseball cards, Angilion?
I don't remember games coming with neat stuff ever since Infocom went out, and I don't even remember anyone else copying Infocom. Basically, though, I think retail games are pretty much useless. Digitally distribute it, and allow you to select an option to order an awesome DNF poster for the first 10k orders or something. "I waited 16 years for this"