Original Mod Made by an unknown author. This is an edit I made of the Version 11 of the Mod which only removes custom monters. This mod may perform differently depending on wether you use gzdoom or Zandronum. This mod is made for the purpose of making it compatible with custom monster mods. I also edited SOME pickups (some armors, SOME ammo pickups, etc.) so they give perk exp when picked up, since the only way to get exp was by killing the custom monsters in the original mod. Not all pickups will give perk EXP. Some custom monster mods may not work properly with this mod. Ideally I should implement a way to make perk EXP get obtained through killing monsters from any custom mod, but sadly I am not experienced with Doom Modding at all and also this mod has a file that I have no idea how to modify (and afaik that file is impossible to decode and modify)
"Ideally I should implement a way to make perk EXP get obtained through killing monsters from any custom mod"
A good mod that would be nice frame of reference for you would probably be a RPG Lite mod called Gun Bonzai which might give you some ideas on what your looking for since it's compatible with any monster mod or weapons mod.
( Github.com )
Universal custom doom maybe too
For the unedited version check it out here Moddb.com
Thx you for the mod... it's really fun to play Doom with KF weaps !