Jimmy wrote:Well, not a specialized version of the
engine per se, but I wanted this to be able to run as an IWAD. I edited zdoom.pk3 to do this. Extract the files to their own folder and run the BAT file, it should work. Though admittedly I should've checked it more thoroughly, or perhaps just found another way entirely to go about it.

Problem with running it batch is that I can't really alter many of the settings, ranging from using the GL renderer (which I need because freelook in software gives me severe motion sickness), to throwing in an add-on if I so chose. You should be able to run it as an IWAD in the official version just fine; plenty of other mods have done it.
If you want, I can spend some time tinkering with it and see if I can repackage it for you. Shouldn't be too hard.
EDIT: Ok, moving mapinfo/square.txt into square_demo_beta.pk3 and renaming it MAPINFO makes the project load perfectly fine as an IWAD from the official version of G/ZDoom. There's one small catch, however...
The colored titlebar on the loading screen won't work this way, because the only method of adding this externally is via GAMEINFO, which will be ignored if it's inside the IWAD. It could be added to a small patch file and loaded as a PWAD to fix that (which is a bit of a clumsy band-aid), or Square can be loaded as a PWAD on top of any Doom-type IWAD (Doom II, Freedoom, etc.) and it should safely paint over anything from those games, meaning the end product would be as intended.