All concept art
Select "Controller Setup" at the options menu. Then, press Down, Down, Down, Up, Down, Up, Left, Left at the controller setup screen. A sound will confirm correct code entry.
All characters in gallery
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, Left, Right, Left, Up, Left, Left, Down 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.
Black costume
Complete 100 City Events, collect all 100 Tokens, and complete all combat tours.