This is a music pack with various songs from different games. You can download it if you want to change the soundtrack to something else, or want to find different music to listen to (the music is quite diverse).

I don't know what else to put here.

To install place the music folder next to the packed folder in resources in the game's files.
EDIT: Track Listing
Title - In Bloom - SY1K1/kamakazi
Basement - Disco Descent - Danny Baranowky
Cellar - Hydrogen - M.O.O.N
Burning Basement - Spike in a Rail - Darren Korb
Caves - Mortars, Baby - Finn M-K
Catacombs - Dance of The Decorous - Danny Baranowky
Flooded Caves - The Bottom Feeders - Darren Korb
Depths - Visitors - Scattle
Necropolis - Meet Matt Stryker - Carpenter Brut
Dank Depths - Krook's March - David Wise
Womb - Regurgitation Pumping Station - Kyle Gabler
Scarred Womb - Crimson - Scott Lloyd Shelley
Cathedral - Meat Continuum - Ridiculon
Chest - Aquaduct Assault - David Wise
Sheol - Hell Toupé - Ridiculon
Dark Room - Boss 3 - Scott Lloyd Shelley
Blue Womb - Pale Watchers- Darren Korb

Boss - Boss 1 - Scott Lloyd Shelley
Boss Alt - Enemy Approaching - Toby Fox
Ambush - Boss 2 - Scott Lloyd Shelley
Mom -The Battle of Lil' Slugger - Danny Baranowsky
It Lives - Double Fucking Rainbow - Chris Christodoulou
Isaac - Plantera - Scott Lloyd Shelley
Satan - Punch Bowl - David Wise
??? - Tropic of Cancer
The Lamb - Moon Lord - Scott Lloyd Shelley
Hush - Momentum Mori - Danny Baranowsky
Ultra Greed - Crocodile Cacaphony - David Wise

Calm - Burning Man - Kyle Gabler
Secret Room - Graphics Processing Unit - Kyle Gabler
Shop - Graze The Roof - Laura Shigihara
Library - Rain Rain Windy Windy - Kyle Gabler
Arcade - Betus Blues - Danny Baranowsky
Devil - Endless Hallway - Alias Conrad Coldwood
Angel Room - Maneuvers - SY1K1/kamakazi
Death - Best Of Times - Kyle Gabler

^Go buy their stuff! (if you can)^