odamex: odamex (Online Doom Multiplayer Experience)

Odamex (Online Doom Multiplayer Experience) is a modification of DOOM
to allow players to compete with each other over the Internet using
the client/server architecture.

To hear in-game music, install either eawpats or freepats, and make
sure the Options -> Sound Options -> MIDI System Backend option is
set to "SDL Mixer" [note: music not working in -current as of October
2021].

Optional dependency: If portmidi is installed, odamex will be built
with it. This allows odamex's in-game music to be directed to a
separate MIDI synthesizer application, or a hardware MIDI synth.

You'll also need the game data (WAD file) from one of the following:

Shareware Doom v1.9 (DOOM1.WAD, aka 'doom_shareware_data' SBo build)
Ultimate Doom v1.9 (DOOM.WAD)
Doom II v1.9 (DOOM2.WAD)
Final Doom: TNT Evilution v1.9 (TNT.WAD)
Final Doom: The Plutonia Experiment v1.9 (PLUTONIA.WAD)
FreeDoom >=0.6.2 (FREEDOOM.WAD aka 'freedoom' SBo build)

Place the WAD file(s) in /usr/share/games/doom. The filenames can be
all lowercase (doom.wad) or all uppercase (DOOM.WAD).

Optional dependency: miniupnpc (auto-detected at build time). This
adds support for UPnP to odasrv (the odamex server). It has no effect
on odamex (the client) or odalaunch (the launcher).