Press L, Up, X, Up, R, Y at the world selection tree.
Show Calabash locations
Pause game play, then press A, L(2), R, A, Down, A, R.
All gallery items
Press B, Up, B(2), L, Y at the gallery screen.
Successfully complete the game to unlock two bonus levels and concept artwork. To view the artwork and play the levels, select "Gallery" at the "Options" menu.
Golden clock icon
Successfully complete a level with a fast time. The message "Faster than the wind!" will appear, and the clock icon next to your completion time will be golden.