To select a stage, go to the jukebox and press C on each one of these numbers: 14, 15, 18, 5, 13, 1, 3, 18, 15, 6.  Next select a number from 1 to 6 and press C and you will be taken to the corresponding stage.

For unlimited health, go to the jukebox and press C on each one of these numbers: 3, 12,17,2, 2, 10, 2, 7, 7,11.