Successfully complete the game, then start another game in special mode. Only characters that survived will have an alternate costume.
FMV sequences
Successfully complete the game to unlock a making of, behind the scenes, and two music videos.
Gallery 1
Successfully complete the game under hard difficulty setting.
Gallery 2
Successfully complete the game in the special mode.
Laser-sight pistol
Successfully complete 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.
Morgenstern bat
Successfully complete the game, then start another game in special mode.
Alternate Background Menu...