'Determination' serves as Undertale 's game over theme.
In Deltarune, although the motif makes a cameo appearance during a fake death in gamover_short.ogg, it's primarily used as a sort of B-section for the 'Rude Buster' leitmotif.
The motif often progresses from a standard variation, 'Determination A':
('Determination A' as heard in Determination)
Into a slightly different variation, 'Determination B':