Insert Disc 2. To get a normal text menu instead of the graphical interface, highlight the cauldron in the lower left corner of the screen, the press Right to highlight the apple. Press Enter to toggle the menu.
Disc production credits (Platinum Edition)
Insert Disc 2 and go to the wishing well. Highlight "History" and press Left to display an option for the disc's production credits.
Funny Magic Mirror comments (Platinum Edition)
Enter any menu screen where the Magic Mirror is present and do nothing. Eventually the Magic Mirror will say something silly, such as "I don't have all eternity, you know. No, wait, I do." This can be done on both discs.