Update: As of v0.8.0 (currently unreleased), no longer requires UKUIHelper to work

UKMusicReplacement

Ultrakill mod allowing users to use custom songs in regular (non boss or special) levels

Installation (Ignore if you're on thunderstore)

Download and install UKUIHelper for the mod to work. The releases contain a custom song named "Stolen Heaven" for 4-1 and 4-2 by triageGremlin, but if you build the mod yourself, it won't come with any song.

How to add custom songs

To add custom songs, open "CustomMusic" in the mod folder, create a folder with your song pack name then another one inside named with the number of the level you want to replace the music from (ie "4-1","1-2", nothing more, nothing less) and add your 2 songs, one must be named "clean" and the other "battle". They must be either an ogg, wav or mp3 file or they won't work.