All characters
Select "Controller Setup" at the options menu. Then, press [Right], [Down], [Right], [Down], [Left], [Up], [Left], [Right] at the controller setup screen. A sound will confirm correct code entry.
All comic covers
Select "Controller Setup" at the options menu. Then, press [Left]x2, [Right], [Left], [Up], [Left]x2, [Down] at the controller setup screen. A sound will confirm correct code entry.
All concept art
Select "Controller Setup" at the options menu. Then, press [Down]x3, [Up], [Down], [Up], [Left]x2 at the controller setup screen. A sound will confirm correct code entry.
All landmarks
Select "Controller Setup" at the options menu. Then, press [Up], [Right], [Down], [Left], [Down], [Up], [Right], [Left] at the controller setup screen. A sound will confirm correct code entry.