Game Data --------- gzdoom is only a game engine. To actually play the game, you'll need the game data (IWAD file) from one or more of the supported games. These include Doom, Ultimate Doom, Final Doom, FreeDoom, Heretic, Hexen, and Strife. Place the .wad file(s) in /usr/share/games/doom. If you don't own any of the supported games, you can install one or more of these slackbuilds.org packages to get a playable game: freedoom, doom_shareware_data, heretic_shareware_data, hexen_demo_data Sound Backend ------------- The default sound backend is FMOD. If OpenAL was found when the package was built, it can be used instead of FMOD. From the main menu: Options -> Sound Options -> Sound Backend. If you have issues with positional audio, try switching to OpenAL. However, some mods (notably Brutal Doom) require FMOD for correct audio support. Unfortunately there are probably some other mods that only work with OpenAL :( If you use FMOD, set "FMOD Options -> Output System" to either "ALSA" or "PulseAudio". Otherwise, the default is OSS emulation, which doesn't share the soundcard nicely with other apps. Music Support ------------- To hear the in-game music, there are several options. In the game menu, select "Options | Sound Options" and set "MIDI Device" to one of the below: 1. FMOD (the default) - Install ff8dls and set the console variable snd_midipatchset to "/usr/share/sounds/dls/ff8.dls" (from the in-game console or by editing ~/.config/gzdoom/zdoom.ini). Alternatively, if you dual-boot with Windows, use something like /dosC/windows/system32/drivers/gm.dls (replace dosC with the mountpoint of your C: drive in Windows). 2. FluidSynth - Install fluidsynth (before building gzdoom) and fluid-soundfont. 3. Timidity - Install TiMidity++ and either eawpats or freepats, and set up /etc/timidity/timidity.cfg to use it. 4. GUS or OPL - Nothing extra required; these are software emulations of classic soundcards from the early 1990s. They may sound "clunky" to modern ears, but they may also bring back fond memories for long-time Doom players.