Secrets and Codes
Hidden Puzzle Game
When you're on the ship, hold down the A button and press the B button 55 times to access the hidden puzzle game.
World Map
While on the world map, press B and Select at the same time, and you will see the world map.
Secret Invisible Guard
In the first castle, there is what appears to be an empty space right above Queen Jane's room and below the person going right and left. Check the lower right corner of this area to find out that there is an invisible person here. Talk to him and he will tell you something before and after you save Princess Sarah.