From WiKirby, your independent source of Kirby knowledge.
"Stage 1" is a theme from Kirby's Block Ball that is associated with the game's first stage as the name implies. A short excerpt of it can also be heard in the game's staff credits music.
The theme's intro is rather simple and straightforward starting with the backup notes frequently ascending up a supertonic scale between the octaves, similarly to a glissando, with the bass corresponding in perfect octaves. The first section of the melody is entirely reminiscent of the well-known "Invincible Candy" theme from the main series of games. Soon after, the theme modulates to the second section in C major with the lead notes distributing a rising sequence between the tonic and dominant timbres. Another modulation occurs as some whole notes create a tonal resolution back down to A major, concluding in a long mediant note, thus looping the track.
Kirby's Block Ball
As mentioned above, the theme plays in the first stage, and its motif is featured in the ending theme.
Kirby's Dream Collection Special Edition
In Kirby's Dream Collection Special Edition, the theme plays when displaying the Kirby's Block Ball entry in Kirby's History.