This is a small minimod for Doom 1 and Freedoom Phase 1 that allows Doom 2/Phase 2 monsters to spawn
in place of other Doom 1/Phase 1 monsters, it works very simple thanks to the GZDoom filters folder,
This should work with most mods, I tested it and it runs well with Complex v27,
Morph64, Brutal Doom Platinum and many more, may not work with mods that replace the editor numbers for Doom 1's
monsters.

Feel free to use this in your own mods, no credits needed, as well as tweaking it or adding in some other stuff
I can't claim ownership over this stuff really, the code is simple and the assets aren't quite mine.