After finishing the game you will unlock a making of, behind the scenes, and two music videos.
Finish the game under the normal or higher difficulty setting, then start another game in special mode. The first available gun will now be a pistol with a laser sight.
Finish the game in special mode.
Finish the game, then start another game in special mode. REMEMBER: Only characters that survived will have an alternate costume.
Finish the game
Alternate menu background
Finish the game.
Finish the game, then start another game in special mode.
Finish the game under hard difficulty.