MGM Home Entertainment’s release of the animated Beatles classic is loaded with hidden features. 14 or so come to mind immediately, and I wouldn’t be surprised if there are more to be found.
Go to the disc’s main menu and press the arrow up key. A part of the Yellow Submarine will be highlighted, the first hidden feature when you press the “Enter” key on your remote control. But from here you can also go left, right, and further up to highlight all different parts of the submarine to bring up small animations and sounds.