Have the Game Boy Advance game Gyakuten Saiban in the cartridge slot.
You can fast forward through long conversations byholding down the forward arrow on the bottom screen with the stylus.A fast forward symbol will appear and the conversation will becompleted a lot faster than normal.
During the credits after completing Case 5, the touch screen will show fingerprint powder being applied and blown away to reveal the credits. After every few screens of credits, a dialogue scene takes place with a character from the game. During these scenes, tap the touch screen as though applying fingerprint powder to it, and blow it off (just like in the actual game) to reveal a hidden drawing of the character that is on the top screen.