You're welcome.
I completed a 2nd run to see whether the bug would return, but this time the game played flawlessly.
From what I can remember from my first playthrough though I seem to have encountered the bug after dying once (I think but I'm not 100% sure) the game seemed fine at first but the sound deteriorated as I progressed to the latter levels.
It got way worse in level 8 when you go through the room with the blade traps that contains the staff.
I suggest if you ever update the game again to add a level select option because if you get to level 6 with low hp then I suspect some players are going to struggle to get past the snakes (or you could add a small potion at the very start).