Thanks for playing!
So there is background music and I kept the volume low intentionally just to convey a calm and sad ambience. I thought the silence will have a deeper impact in the story. Same reason I didn't do voice acting despite having voice acting in my game the previous jam. There were two instances of background music, the first time the protagonist stops time and then at the very end of the cutscene. It was silence in the middle (there was SFX throughout though, it was never complete silence).
Maybe you could watch the YT video and increase the volume a bit? Your comment leads me to believe that maybe none of the sounds (music and sfx) played when you watched it. It should easily be audible without headphones too.
Thanks again for the review. I'm stressing this much with the audio cause I did spend a great deal of time making it sound natural.