Installing GZDoom on the Steam Deck - [How to Tutorial] 

GZDoom is a tool for playing classic doom. Think of it like a Doom emulator, and the .WAD files can be thought of as the ROMs that it loads. ZDL is the file that gives us a GUI for telling GZDoom to load with mods.
Link to gzdoom.sh contents: pastebin.com/G...