Press II, I, II, II, I, II at the title screen. Then, hold Select and press Run. A level selection option will now be available. To access levels 4 to 6, hold Select while the level selection option is highlighted.
Sound test
Hold Select and press Start at the title screen. A sound test option will appear on the main menu.
View messages
Press II, I, I, II, Select, Run or I, II, II, I, Select, Run at the title screen to view two different messages.