Continue (Japanese version)
At the title screen, hold down right and simultaneously press B three times (pressing A also works), then hit start.
Level Select
At the title screen do the following: Hold down Right, pres B 3x then press Up, and release it. Press B 3 more times. Press Left, then release and press B 3 more times. Press Down, release, then press B 3 more times. Finally press Start.
See the bonus message
Successfully complete both of the quests, and then press A, B, Up, Down, A, B, Left, Right.
