Do 20 second interlude tunes count as music?

[Gors]

The definition of Sound Effects is quite shady in this point, but jingles should be included in the sound effects archive, preferrably in a folder separated from the rest.

Those sound bits that play when doing small actions (walking, getting coins, winning the level/game) are sound effects (footsteps, blips, fanfares, respectively). In simpler words,

Soundtrack is generally the music or ambient sound whose generating event is the start of the level or screen, or plays randomly without needing an actual action to occur. This covers title music, menu, level themes, cutscenes.

Sound Effect is the music or sound bit whose generating event is a definite game action. Those include sounds generated by the characters/enemies, cursors, fanfares and game over jingles, if they are small and doesn't loop. (think SMB's game over jingle).

tl;dr if it's long and made to be listened for a long time, it's music. If it's short and made to be listened occasionally, it's sound effect.