Deltarune has a few songs with an interesting rhythmic pattern I'd like to coin as the "Heartbeat leitmotif"
Now, I don't know if this is enough on its own to be a leitmotif but I do know that non-melodic musical patterns can be considered leitmotifs.
I've basically found 4 songs(so far) songs, 1 in each chapter, that have a sort of pounding sound. Specifically, there is 2 pounding sounds close to each other and another 2 pounding sounds with slight separation between the first two. And this pattern repeats a lot.
In-game, the first song I've found is 'The Chase' in chapter 1. It is the booms in the song. Acually, it's used in every chapter when a 'chase' happens. I've tested all of these in audacity to make sure they line up(accounting for tempo ofc) and they do.
In the second chapter, Berdly's Snowgrave fight has this rhythm. His normal music does, too, but only briefly and it's sort of in the background. In the files, the song is titled "berdly_battle_hearbeat_true.ogg" which is why I'm calling this the "Heartbeat leitmotif". Also a good time to note that the rhythm sounds very much like a heartbeat.
The third chapter has 'Crickets'. It's hard to tell at first because each pattern is separated by an inconsistent amount of time to resemble nature. However, each 1-2__1-2__ themselves are still on point with the other songs. And it's the only prominent sound in the track.
Finally, there is 'Crumbling Tower' in chapter 4. Like, the last one, the start of the song has longer pauses between each pattern. It returns to typical spacing mid-way through. 'GUARDIAN' and 'SPAWN' also have the pattern but for less time and less prominently.
See, if these were just random songs, I wouldn't be making these posts. But these are all either important songs or directly related to suspense/heartbeat. 'The Chase' is most obviously related to your heartbeat as it plays in suspenseful moments, including the first ever dangerous moment in the game(also the first to threaten you soul). It makes sense for Berdly as well, both because he's really really scared and because the SOUL is important to Snowgrave route. 'Crumbling Tower' is chapter 4's "OH SHIT" moment and has a light mechanic with the soul so that checks out. The only odd-ball here is 'Crickets' but it literally plays outside of the bunker past midnight so it is none the less relevant in some way.
Thoughts?