Interesting, haven't noticed that. I did add a background noise to the menu level to add a bit of spice. Looks like it still runs even though the menu is up (probably because it's pre-loaded). Will remove it in the next update.

For some reason, with this mod on, you can hear the background lava ambient sound even in-game. It's very obvious if the game's paused. You can hear some humming ambient noises.

That's hella cool