Deathmatch Simulator is a GZDoom mod that aims to provide players with a 100% authentic simulation of an actual, real-world online deathmatch.
You can run the fauxdm-dev folder directly in GZDoom, if you're feeling spicy and/or developer-y. Otherwise, run the batch file or MAKEFILE to build a PK3 file which can be run in GZDoom normally.