I think the game changes the menu track when you go to the settings, and that track's volume is lower than the main menu's music, this makes it hard to gauge the correct sound level. Still, I'd say that even setting them to the bare minimum the slider allows without being 0, is still way too high. My system audio is at 30, this means that what people usually use (100) in the device's audio volume settings, would sound with more than triple the strenght.
The game is neat, it plays smoothly, and the art style and presentation is on point, but i seriously encourage you to address the volume levels and related settings of the game.
Cheers ;)