Mod the Gungeon is deprecated, a better version of this mod is integrated into the MTG API: https://enter-the-gungeon.thunderstore.io/package/MtG_API/Mod_the_Gungeon_API/
Source Code: https://github.com/Goldenrevolver/ButcherMod (old repository: https://github.com/SpecialAPI/ButcherMod)