Average Isaac enthusiast

for a more clear explaination of how it works here's a vid that goes into it: https://youtu.be/tKktr-sqPwc

I suggest you use the extract folders app isaac has in its steam files if you want to change more of it's ost that it plays

yo thanks fam

Here are the songs in the video:

"kave diluvii (flooded caves) loop": https://youtu.be/5okZQKELZrY

(don't put in the afterbirth folder, in music make the folder "fight ogg" and place this in there)
"chest fight": https://youtu.be/1Qtr-IlViQ8

"morituros (dead womb boss) loop": https://youtu.be/ApS3KhzgHcQ

(their specific file names in order for the songs to work)

to get them to work. record or download the songs you want and save them as a .ogg file, go to binding of isaac mods folder in the steamapps folders, create a folder for those songs specifically make the following folders resources > music > afterbirth > (name the song exactly as the list above quoted.

Good luck