If you ask me, this is the kind of thing that should just be included or free. If you want to entice me, give me a cool little figurine or keychain. I am a sucker for those.
Anyway, for those of you who do like extra levels, GameStop is offering a code with pre-orders that gives players a chance to play through the Palazzo Mecici as the game’s protagonist, Ezio.
Check out a pic and the story here: Kotaku