About
Freedoom is a completely free and open-source set of DOOM-engine game data created entirely by community volunteers, licensed under Creative Commons. It provides two full single-player campaigns (Phase 1 and Phase 2) and a deathmatch-focused WAD (FreeDM), all designed to be fully compatible with any DOOM source port. Because Freedoom replaces the commercial id Software IWADs, players can experience the full DOOM engine experience without owning the original games. It also acts as a base for the vast library of community-made DOOM maps and mods, most of which run against Freedoom without modification.
Identity
Launch
- Binary
- gzdoom
- Options
- -iwad freedoom1.wad
- Needs files
-
- freedoom1.wad
Runtime
- Runs as
- Native Linux
- Proton
- not needed
⚙ Setup notes
Engine: Native Linux via GZDoom (Flatpak: org.zdoom.GZDoom on Flathub/Discover).
Install: Download Freedoom WADs from freedoom.github.io and place them at ~/.var/app/org.zdoom.GZDoom/.config/gzdoom/ (the Flatpak config path). GZDoom auto-detects IWAD files at launch.
Launcher: Alternatively use GZDeck (github.com/flegald/GZDeck), a launcher built specifically for GZDoom on Steam Deck that simplifies mod/IWAD launching and adds the --no-sandbox launch argument required by the Flatpak. (Note: GZDeck is no longer actively maintained, but still works; community forks exist.)
Non-Steam game: For adding to Steam as a non-Steam game, set launch options to: --no-sandbox -iwad freedoom1.wad (or freedoom2.wad / freedm.wad).
Alternative: RetroDECK also bundles GZDoom and supports Freedoom WADs.
WADs: Phase 1 replaces Doom 1, Phase 2 replaces Doom 2, FreeDM is a deathmatch-focused standalone WAD.
The one thing to know
Free download: Freedoom WADs are completely free — download from freedoom.github.io directly.
Source port: Requires a DOOM source port (GZDoom recommended via Flatpak in Discover).
Install: Place WADs at ~/.var/app/org.zdoom.GZDoom/.config/gzdoom/ for automatic detection. The GZDeck launcher simplifies Deck-specific setup.
Artwork: sgdb_id here points to Phase 1; Phase 2 is at steamgriddb.com/game/5273736.
Controller: Multiple local-multiplayer controllers may conflict with Steam Input — use single controller or external KB+M.
Community guides
Write-ups and threads from people who got this (or a similar) game running. deckport links to them — it doesn't reproduce them.
Get the artwork
deckport never hosts game images. Open this game on SteamGridDB, pick
the cover / hero / logo / icon you like, and drop them into the
game folder under .deckport-art/ before you push it to the
Deck. The importer files them under the right names automatically.
Run it on your Deck
Two files: the one-time importer (deckport.py) in your
Deck's home folder, and this game's install helper. Copy the game
into ~/Games and run the helper with Steam closed — it
writes the recipe (binary, launch options)
and registers the shortcut with artwork.