Hidden audio (Collector's Edition version)
At the "Bonus Materials" screen, select the "Bits And Pieces" option and view that feature until it ends. Return to the main menu and select the "Begin The Terror" option to start the movie. An evil voice will state "You will die" before the movie starts.
Hidden clip (Book Of The Dead Limited Edition)
At the main menu, select the "Extras" option. Advance to the second extras screen. Highlight the "Fanalysis" option then press Left until the skull is highlighted. Press Enter to view a clip about a Halloween showing of the movie.
Makeup effects test (Book Of The Dead Limited Edition)
At the main menu, select the "Extras" option. Highlight the "Trailer" option, then press Left to highlight the fish outline on the left side of the screen. Press Enter to view a makeup special effects clip.