Version 3.5.1 of the Doom engine source-port in a snap, along with a graphical launcher for launching wads and pk3s.
All game files should go into the ~/snap/gzdoom/current/.config/gzdoom. You may have to create a folder or run the game first in order for the folder to show up.
This is my first attempt at making a snap. I might return to this in the future and see what changes I can make to it.
cd to the gzdoom-snap directory and run:
snapcraft
In the same directory, run:
sudo snap install --force-dangerous *.snap
The launcher should appear in your app menu. First run will take a while, but subsiquent loads be normal.