Its a config file that makes GZDoom look and play like vanilla. Obviously, still limited by the capabilities of the engine. It's still going to be GZDoom, but very vanilla-like GZDoom.
To install, drop this next to the GZDoom exe. Warning, this will take priority over your own config if you have one already set up. In that case, i suggest you open both this config file and your own, and compare the differences, and adjust mine to your liking with your changes. Notepad++ has a nice compare plugin that would probably make this easier
To uninstall, just delete it.
Oh, and if you didnt know, if you name the config file gzdoom_portable.ini and you put it next to the exe, you can use a portable installation of GZDoom, no documents folder shenanigans required.
Also, this is for windows users. I havent switched to linux yet so i dont have a config to compare, but if you're a linux user im pretty sure you can either turn off the things yourself because you know this better than i do, or that you can atleast compare your textfile to mine and import the stuff that arent dependent on the operating system.