About
The Dark Mod is a free, standalone stealth game built as a love letter to the Thief series, created by community volunteers who began work in late 2004 using the Doom 3 engine SDK. It launched in 2009 as a Doom 3 total conversion and became a fully standalone free game in 2013.
The base game ships with a training mission and a starter FM (fan mission), with hundreds of additional fan-crafted missions available via the built-in downloader. Each mission is a self-contained stealth scenario set in a dark, Victorian-inspired city. The project remains actively maintained, with version 2.10 (2022) delivering a major rendering upgrade, and new missions continuing to appear regularly.
Identity
Launch
- Binary
- thedarkmod.x64
- Needs files
- none beyond the binary
Runtime
- Runs as
- Native Linux
- Proton
- not needed
⚙ Setup notes
Native: Native Linux 64-bit binary (thedarkmod.x64). No Proton needed for the standard path.
Install: In Desktop Mode, open a terminal and run the one-liner below to download the official installer, then let it fetch the game files automatically. After install, add thedarkmod.x64 from your ~/tdm/ folder as a non-Steam game.
Install command:sh -c 'mkdir ~/tdm; cd ~/tdm; curl -o tdm_installer.linux64.zip https://update.thedarkmod.com/zipsync/tdm_installer.linux64.zip; unzip tdm_installer.linux64.zip; chmod +x ./tdm_installer.linux64; ./tdm_installer.linux64 --unattended'
Proton: Alternatively, Proton can be used with TheDarkModx64.exe if the native path presents issues. A simplified forum install script for Deck is linked below.
Controller: The engine has had gamepad support since TDM 2.09, but no in-game input mappings are active by default (only the main menu). On Deck the easiest path is to apply a Steam Input controller layout (or bind a gamepad manually in-game); some users report it working out of the box on Deck.
Missions: Additional fan missions can be downloaded directly from the in-game mission downloader.
The one thing to know
Completely free and standalone — no owned files or Doom 3 copy needed.
Install: Run the one-liner install command in a Deck terminal (Desktop Mode) to download everything automatically into ~/tdm/. Then add ~/tdm/thedarkmod.x64 as a non-Steam game.
Alternative: The official Deck forum thread has a simplified install script if preferred.
Missions: Hundreds of fan missions are available via the in-game downloader after first launch.
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.