Select the "Extras" option and load a previously saved game file. Select "Game Secrets" > "Enter Code". Enter one of the following symbols in the Alethiometer in the order, top left, bottom left, and top right. The corresponding featurette will become unlocked at the "Featurettes" option at the "Extras" menu.
FEATURETTE - CODE "Audio Session: Dakota Blue Richards" featurette - Compass, Sun, Madonna "Audio Session: Freddie Highmore" featurette - Compass, Moon, Wild Man "Behind the Scenes..." featurette - Alpha/Omega, Alpha/Omega, Compass "Daemon Motion Reference Shoot" featurette - Griffin, Elephant, Owl "Polar Bears in Motion" featurette - Sun, Moon, Wild Man