Hidden menu animations
Press [Up] at the main menu to highlight Inspector Gadget's head, then press [Enter]. If done correctly, Inspector Gadget's head will extend upwards and break the roof. You can also do this with other parts of his body at other menus.
Press [Down] at the main menu until the gear at the lower left is highlighted. Press [Enter] and an object will appear from Inspector Gadget's hat. Press [Right] to highlight another gear. Press [Enter] and a glove will shoot out of Inspector Gadget's hat to catch a baseball.
Alternate menu
Advance to the last chapter and watch the rest of the movie. Press [Up] after the main menu re-appears until the Inspector Gadget 2 logo is highlighted. Press [Play] to view an alternate menu.