Press X, Y, A, B, X, Y, A, B, Start at the title screen. Press Left or Right to select a level, then select the ‘Exit’ option. Begin game play to start on that level.
Hold L + R + Select + Start during game play to return to the title screen.
Hint: Level 5: Extra life:
When you get off the cable car and go down the stairs, just before the end of the huge gray wall are notches above your head. Jump on one, then keep jumping up to the next higher notch. It will take you to an empty space that contains an extra life.