None of those were the issue, I did find the solution though.Forevener wrote: Try the following things, please:
1. Remove zd_extra.pk3 from the load order
2. Check your DOOM2.WAD version
Turns out, it was because I was using a true color renderer.
This happens when starting up with both true color renderers.
However, I can start up with a different renderer, then switch to true color, and it will be fine.
My B. I didn't know true color could do that kinda stuff.
Thanks for the help though, everyone!
*Turns out the game also closes automatically if you go the outpost with the doom software renderer on, I guess I probably should have just listened to the FAQ when it said to play with OpenGL.