So @authorblues and myself picked up Memoirs of Magic which is a free game on Itch.io built on top of GZDoom and we actually got the co-op working. It's a hard game that is kind of oozing quality Saturday morning Style. If you're having issues with getting the multiplayer to work I might have some assistance for you.
Here's a link! https://strawberryoctii.itch.io/memoirs-of-magic
THING TO KNOW 1: THE README IS GOLDEN There's a multiplayer readme that has examples of the strings you're going to need to add between client and host to set up peer2peer multiplayer. This information is good and you should go consume it if you haven't.
THING TO KNOW 2: THE COPY OF GZDOOM MoM IS PACKAGED WITH SEEMS TO BE OLD If you go to https://zdoom.org/downloads and pick up the latest GZDoom (4.10.0 as of writing.) you may have better luck! You're for sure in for a bit of tinkering though.
So we had two major errors get in our way for our session
#1 was crashing. We got connected and running, but the game would tear itself apart. Upgrading to newer GZDoom fixed that. But how do you do that you ask? Great question. GZDoom is the engine that doom is built on top of, and the MoM folder contains a file that ends in ".ipk3" If you copy that file over to your GZDoom alongside a couple of other weird system files (Best to make a little folder backing up the old ones that GZDoom comes with) then GZDoom should see Memoirs of Magic when you fire it up.
#2 Loading saves. We ended up sharing the host save-file across discord and pointing it at a specific location in the launch options that you read the readme and learned how to configure. I also learned that if your file names/paths have spaces in them that can cause problems. At present we're looking at using a dropbox to more directly update save files with, but that hypothesis remains untested.
I'll try to add to this as we learn new things, but the game slaps so far.
