Hidden clip
Enter the "Special Features" screen. Highlight the "Main Menu" option. Press [Left] to highlight an "H" at the left side of the screen. Press [Enter] to see a clip featuring Jung-ah Yum doing martial arts training.
Hidden trailer
Enter the "Set-Up" screen. Select the "Subtitles" option, then highlight the "English" option. Press [Left] to highlight an "H" inside the flashlight. Press [Enter] to view the trailer.