I made the decision to play around with different boss themes for main and alt path a good while ago but i'mma do it again due to some well-justified (albeit short and sweet) criticism:

Boss 1 on main path is now back to normal
Boss 2 on main path now uses the original alt path boss theme
Alt Path Boss and Ambush/Challenge remains the same

The main reason behind these choices is to keep a little closer to the original vision for these tracks (except Ambush, Sloth's theme still works better for it imho). Originally i swapped out these tracks due to them being a little too similar to each other but i think i've chosen some more cohesive tracks with the same vision but just with a little more variance (they all sound fairly similar now but the distinction between them is much more present, kinda like a gradual evolution of the themes). I enjoy the state of these boss tracks now much more than the original vision I had about a year or so ago.

I'll balance the volume of these tracks in a later update if necessary after playing around a little bit with these changes and figuring out what volume level sticks.

Dross, Utero, Gehenna and Mines all have the Rebirth layer type, playing alongside the original track instead of replacing it (even though they use the Rep layer type originally, these tracks' normal samples are significantly quieter in their layer, making them almost inaudible, therefore the Rebirth layer type suits well for them)

Utero finally (hopefully) has a synced layer, Cellar and the Horsemen are still unfortunately unrealistic to sync from my position.

Lil mini update, added some of the original Repented boss tracks into the 'alternate layers and music' folder

Further volume balancing, Mines was still really quiet

Slight volume adjustments:
Made layers for alt path slightly louder, mimicking vanilla Isaac.
Made ashpit and alt path boss jingle slightly quieter again.

Changed Corpse's layer mode to be consistent with alt-path (wasn't playing the layer properly due to missing section of music.xml)

Finally gave the mod a music.xml to better balance audio.

To accompany this, some tracks have had their volume balanced a little bit (e.g. Arcade theme is a little it louder as the track replacing it is slightly on the quiet side, alt boss jingle is a little bit quieter to not be abnormally loud)

Gone through and fixed each layer not being the same track length as their respective base loop. Now every track should be synced to the best of my ability. If due to my meddling, some tracks don't sync anymore, reach out and i will revert this change asap.

(exceptions being utero, cellar and harbinger layers for beast fight as most of the above use drastically different track lengths fsr)

Synced (in theory):
all of ascent
downpour
ashpit
tainted title
cathedral
caves
catacombs

Swapped around main path boss tracks again, boss 1 and boss 2 use Gluttony's and Lust's themes respectively from non-vanilla Repented (still felt kinda samey between the two boss tracks and i just honestly like these two as boss tracks more imho)

Also swapped out Ambush/Challenge Rooms for Sloth's theme for the same reason listed above.

Finally, I've removed the disclaimer at the start of the description and instead bolded and italicised the text at the bottom linking to Broski's work. This is because he's now listed as one of the authors of the project and thus it will now appear under his workshop items as well as my own.

As always, the original tracks should be present in the "alternate layers and music" folder if you wish to change this back.

Changed the Arcade theme to the theme for Fiend Folio D12 rooms. (personally felt it to be a little too upbeat and hype for the area)

Original is still in alternate layers and music if you want to swap it back.

oops forgot to re-add the original layer into alternate layers again.