S.T.A.L.K.E.R. Anomaly + GAMMA · SteamOS field guide

GAMMA on Steam Machine

How to install the GAMMA modpack on a Valve Steam Machine with STALKER GAMMA COMMANDER 1.3.1, including the workarounds this hardware needs. Follow it in order and tick each step as you finish. The last section shows how to remove all of it again.

An unofficial community guide. It isn't affiliated with Valve, the GAMMA team or COMMANDER's developer. It was tested on one Steam Machine in October 2026, so menu names may differ slightly after updates.

App version: COMMANDER 1.3.1
Proton: GE-Proton 11-9
Free space: ~150 GB (100 GB minimal)
Tested: Steam Machine, Oct 2026

Setup 0 / 10

Uninstall 0 / 8

Before you start

Switch to Desktop ModeSteam button → Power → Switch to Desktop. Steps 1 to 9 all happen there.
Plug in a keyboard and mouseYou'll be typing commands in Konsole. GAMMA itself also plays best with keyboard and mouse.
Use the internal SSDGAMMA is a huge number of small files. Loading it from microSD is much slower.
Plan for hoursMost of the time is the GAMMA download. You can stop it, and the app resumes where it left off.

Setup steps

Do these in order. Your ticks are saved in this browser only.

1
Browser + KonsoleDownload the app
Done

On the 1.3.1 release page, download STALKER-GAMMA-COMMANDER-1.3.1-x86_64.AppImage into Downloads. This guide was tested with 1.3.1. Newer releases, including the "Unstable" pre-releases, may change the steps.

Open Konsole, then move the file somewhere permanent and make it runnable:
```
mkdir -p ~/Applications && mv ~/Downloads/STALKER-GAMMA-COMMANDER-1.3.1-x86_64.AppImage ~/Applications/ && chmod +x ~/Applications/STALKER-GAMMA-COMMANDER-1.3.1-x86_64.AppImage
```
2
Discover + KonsoleInstall Protontricks so the installer stops asking for it
Done

Open Discover, search Protontricks and install it. Or install it from Konsole:
```
flatpak install -y flathub com.github.Matoking.protontricks
```
The Discover version has no plain protontricks command, so COMMANDER can't find it. Add a two-line helper that it can find:
```
mkdir -p ~/.local/bin && printf '#!/bin/sh\nexec flatpak run com.github.Matoking.protontricks "$@"\n' > ~/.local/bin/protontricks && chmod +x ~/.local/bin/protontricks
```
Check it works:
```
~/.local/bin/protontricks --version
```
Expect a line like protontricks (1.x.x).

Why: COMMANDER won't install the game's runtimes until it finds protontricks, even though the GE-Proton setup never actually runs it. Don't install system Wine; you don't need it.
3
COMMANDER · Install pageOpen COMMANDER and create the game folders
Done

In Dolphin, open Applications in your home folder and double-click the AppImage. It opens the normal desktop window; it won't offer Deck Mode on its own here.
1. Go to Install.
2. Pick a base folder in your home, for example Games/GAMMA.
3. Click Create folders. That makes the Anomaly, GAMMA and cache folders.
COMMANDER · Play pageInstall GE-Proton
Done

On Play, click Install GE-Proton and wait until the button reads GE-Proton installed ✓.

Do this before step 6. Each Proton version keeps its own Windows setup, so the runtimes in step 6 need to go into this one.
5
COMMANDER · Install pageInstall GAMMA
Done

Click Install → Install GAMMA. It installs Anomaly first, then every GAMMA addon, and shows progress for each one.
- Minimal mode saves about 50 GB by deleting the downloaded archives. Repairs then have to download them again.
- If the download stops partway, COMMANDER offers Resume GAMMA Installation next time you open it.
Keep the machine awake. The desktop window doesn't stop the Steam Machine from sleeping during the download. Turn off automatic sleep in System Settings → Power Management first. Or run the install from Deck Mode's Install tab (press X), which keeps the machine awake on its own.
6
COMMANDER · Deck ModeInstall the game's runtimes from Deck Mode
Done

The desktop window's Install Dependencies button stops with "Wine is required". That's a known gap on SteamOS, so use Deck Mode's button instead:
1. On the Dashboard, click the small Steam Deck icon next to Quick actions. COMMANDER restarts in Deck Mode.
2. Go to the Install tab and choose Install Dependencies (Y on a controller).
3. When it finishes, use Settings → Exit Deck Mode to return to the desktop window.
It installs winetricks, then umu-run (both into ~/.local/bin), then these Windows runtimes through GE-Proton:

d3dcompiler_43d3dcompiler_47d3dx10d3dx11_43d3dx9quartzdx8vbvcrun2022
COMMANDER · Play pageTest the game once in Desktop Mode
Done

On Play, check that the runner shows GE-Proton, then click Launch Game. The first launch downloads Steam's Linux runtime, so give it a few minutes before the game window appears.

If it reaches the main menu, quit the game normally. Problems are easier to fix here than in Game Mode.

Nothing happens, or Mod Organizer closes after a few seconds? On GE-Proton 11-9 that's a crash in Proton's VR support. The fix is one command: see Mod Organizer closes straight away under troubleshooting.
COMMANDER · SettingsAdd COMMANDER to your Steam library
Done

Click Settings → Steam → Add COMMANDER to Steam. Steam closes, the shortcuts are written, and Steam starts again. You get two entries: STALKER COMMANDER and STALKER COMMANDER DECK.

Desktop Mode only. This closes Steam, which would end a Game Mode session. COMMANDER can't tell it's in Game Mode on a Steam Machine, so it won't stop you.
9
Steam · Desktop ModeSet the Deck Mode launch option
Done

In Steam, right-click STALKER COMMANDER DECK → Properties, and replace Launch Options with:
```
SteamDeck=1 %command% --deck
```
Why: COMMANDER only recognises the Steam Deck's hardware names, and the Steam Machine reports a different one. SteamDeck=1 tells it it's on SteamOS, so Deck Mode opens full screen on your TV.
10
Game ModePlay from the couch
Done
1. Double-click Return to Gaming Mode on the desktop.
2. In your library, open the Non-Steam collection and start STALKER COMMANDER DECK.
3. On the Dashboard or Play tab, press X to play GAMMA.
If the game hangs, press the Steam button to get back, open COMMANDER's Play tab and choose Force Stop Game.

Deck Mode controls

COMMANDER reads the controller directly, so Steam's default controller layout works in Game Mode.

Button	Action
D-pad / left stick	Move (hold to repeat)
`A`	Select or toggle
`B`	Back
`X`	The screen's main action
`Y`	The screen's second action, or search
`L1` / `R1`	Previous / next tab
`L2` / `R2`	Page up / down
`☰` Menu	Play GAMMA, Exit Deck Mode or Quit
`⧉` View	Controls help

Screen	`X`	`Y`
Dashboard	Whatever the banner says: Play, Install, Resume or Update	Re-check
Play	Play GAMMA (Force Stop while running)	Open Mod Organizer
Mods	Category menu	Search
Update	Check or apply updates	Show changes
Install	Install or resume GAMMA	Install dependencies

If something goes wrong

Mod Organizer closes straight away and the game never starts: You click Play, Mod Organizer flashes up or doesn't appear at all, and it's gone within about 10 seconds. COMMANDER's ~/.config/stalker-gamma/logs/commander.log shows wrapper exited code=3, and files named ModOrganizer-2.5.2-*.dmp appear in ~/Games/GAMMA/gamma.; Cause: GE-Proton 11-9's VR support (wineopenxr) crashes when no VR headset software is installed, and takes Mod Organizer down with it. GAMMA doesn't use VR, so it's safe to turn off.; Fix: close the game first. The fix has to run with the same GE-Proton build COMMANDER uses, so check its folder name:; ls ~/.local/share/Steam/compatibilitytools.d; If it isn't GE-Proton11-9-x86_64, change that part of the next command to match. The command turns the VR component off in the game's Wine prefix, so every launch picks it up and you don't need to change COMMANDER's settings.; WINEPREFIX=~/Games/umu/umu-default PROTONPATH=~/.local/share/Steam/compatibilitytools.d/GE-Proton11-9-x86_64 ~/.local/bin/umu-run reg add 'HKCU\Software\Wine\DllOverrides' /v wineopenxr /d '' /f; It should end with reg: The operation completed successfully. To check it stuck:; grep '"wineopenxr"' ~/Games/umu/umu-default/user.reg; Expect "wineopenxr"="". Then click Play again.; If you ever delete or repair the Wine prefix, run the fix again. Once a newer GE-Proton fixes the crash, you can undo it: run the same command, but replace everything from reg add onwards with reg delete 'HKCU\Software\Wine\DllOverrides' /v wineopenxr /f.
The desktop Install page says "Missing Dependencies: Wine is required": Expected on SteamOS. Install the runtimes from Deck Mode (step 6). Don't install Wine.
Deck Mode says "protontricks could not be installed": The helper from step 2 is missing or not runnable. Run the --version check from step 2, then try again.
In Game Mode, COMMANDER opens as a small window or as the desktop layout: The launch option is missing. Redo step 9 on the STALKER COMMANDER DECK entry.
"Add to Steam" can't tell which Steam account to use: Do it by hand in Desktop Mode: in Steam, choose Add a Game → Add a Non-Steam Game, browse to the AppImage in ~/Applications, then set the launch option from step 9 on it.
The game crashes right away after you ran Wine or winetricks yourself: Running another Wine against the game's Proton setup damages it. Use Utilities → Repair Wine prefix, then install the runtimes again (step 6).
COMMANDER offers to update itself: Newer versions may change menus or fix the gaps this guide works around. Staying on 1.3.1 keeps every step here accurate. GAMMA's own addon updates are a separate thing and are fine to apply.

Why the Steam Machine needs extra steps

COMMANDER was built for the Steam Deck, which runs the same SteamOS. Two parts of it don't recognise a Steam Machine yet.

It doesn't know the hardware. It checks for the Deck's internal names, Jupiter and Galileo. The Steam Machine reportedly identifies as Fremont. To spot Game Mode it also needs SteamDeck=1, which may not be set on a Steam Machine. Step 9 sets it.
Its dependency check is stricter than it needs to be. It wants protontricks, and the desktop page also wants system Wine. SteamOS ships neither, and the GE-Proton route never uses either. Steps 2 and 6 get around it without changing the system.

Uninstall everything

Removes GAMMA, COMMANDER and every tool the setup added. SteamOS itself needs no undoing, because the setup never changed it. Work in Desktop Mode and in this order: steps 1 and 2 need COMMANDER, so do them before you delete it. Copy the commands exactly rather than retyping them.

1
COMMANDER · UtilitiesRemove the game with Full Uninstall
Done

Open COMMANDER and click Utilities → Full Uninstall. In Deck Mode it's on the Utilities tab, under Uninstall.
- The confirmation lists the exact folders it deletes: Anomaly, GAMMA and cache. Check they're the ones inside your GAMMA folder before you confirm.
- It backs up your saves, user.ltx and MCM settings first, to ~/.local/share/stalker-gamma-commander/backups. If that backup fails, it deletes nothing. Mods you added yourself aren't backed up.
- This frees most of the space, roughly 100 to 150 GB.
More than one profile? Switch to each one on the Profiles page and run Full Uninstall again for it.
2
COMMANDER · Play pageRemove GE-Proton (optional)
Done

On Play, click Manage GE-Proton…, then Remove All Unused, or select a build and click Remove Selected. COMMANDER won't remove a build that a Steam game is set to use.

Skip this if you use GE-Proton for other games.

If you already deleted COMMANDER, remove the builds from Konsole instead. Steam stops listing them after its next restart:
```
rm -rf ~/.local/share/Steam/compatibilitytools.d/GE-Proton*
```
3
SteamRemove the Steam shortcuts
Done

In your Steam library, right-click STALKER COMMANDER → Manage → Remove non-Steam game from your library. Do the same for STALKER COMMANDER DECK. Its launch option from setup step 9 goes with it.

"Add to Steam" also saved a backup of your old shortcut list. Delete it with:
```
rm -f ~/.local/share/Steam/userdata/*/config/shortcuts.vdf.gammagui.bak
```
4
KonsoleDelete COMMANDER, its settings and its menu entry
Done

Quit COMMANDER first. Then delete the app:
```
rm -f ~/Applications/STALKER-GAMMA-COMMANDER-*-x86_64.AppImage
```
Its settings, profiles and logs:
```
rm -rf ~/.config/stalker-gamma
```
Its app-menu entry, icon, and the start-at-login entry if you turned that on:
```
rm -f ~/.local/share/applications/stalker-gamma-commander.desktop ~/.local/share/icons/stalker-gamma-commander.png ~/.config/autostart/stalker-gamma-commander.desktop
```
If you made desktop shortcuts from the Play page, delete them from your Desktop too.
5
KonsoleDelete the Wine prefix and the empty folders
Done

The game's Windows setup, with the VC++ and DirectX runtimes from setup step 6, survives Full Uninstall on purpose. Delete it:
```
rm -rf ~/Games/umu/umu-default
```
This is umu's default prefix. If you run other Windows programs with umu-run yourself, they may use it too. If you changed the prefix on COMMANDER's Play page, delete that folder instead.

Then remove the folders that are now empty. rmdir only deletes empty folders, so it can't remove anything you still keep in them. If you picked a different base folder in setup step 3, use that path instead of ~/Games/GAMMA.
```
rmdir ~/Games/GAMMA ~/Games/umu ~/Games 2>/dev/null
```
6
KonsoleRemove umu-run, winetricks and Protontricks
Done

Keep any of these you use for other games. On a fresh SteamOS, all of them came from this setup.

The three commands in ~/.local/bin, including the Protontricks helper from setup step 2:
```
rm -f ~/.local/bin/umu-run ~/.local/bin/winetricks ~/.local/bin/protontricks
```
The Linux runtime umu downloaded on the first launch, and winetricks' download cache:
```
rm -rf ~/.local/share/umu ~/.cache/winetricks
```
The Protontricks app itself. The second command removes Flatpak runtimes that no installed app needs any more:
```
flatpak uninstall -y com.github.Matoking.protontricks && flatpak uninstall -y --unused
```
Or remove Protontricks in Discover, under Installed.
7
KonsoleDelete your save backups (optional, last)
Done

Full Uninstall put your saves and game settings here. Only delete them if you're sure you won't come back to GAMMA. To keep a copy in Documents first:
```
cp -r ~/.local/share/stalker-gamma-commander/backups ~/Documents/gamma-save-backups
```
Then delete COMMANDER's data folder:
```
rm -rf ~/.local/share/stalker-gamma-commander
```
8
System Settings + KonsoleTurn sleep back on and check nothing is left
Done

If you turned off automatic sleep in setup step 5, turn it back on in System Settings → Power Management.

Then list anything that's still there:
```
ls -d ~/Games/GAMMA ~/Games/umu ~/Games/proton ~/.config/stalker-gamma ~/.local/share/stalker-gamma-commander ~/.local/share/umu ~/.local/bin/umu-run ~/.local/bin/winetricks ~/.local/bin/protontricks ~/.local/share/Steam/compatibilitytools.d/GE-Proton* 2>/dev/null
```
No output means everything is gone. Anything listed is still there, which is fine if you kept it on purpose, such as GE-Proton or your save backups. ~/Games/proton only exists if you ever picked a Steam Proton runner; delete it with rm -rf ~/Games/proton if it shows up.

Before you start

Setup steps

Browser + KonsoleDownload the app

Discover + KonsoleInstall Protontricks so the installer stops asking for it

COMMANDER · Install pageOpen COMMANDER and create the game folders

COMMANDER · Play pageInstall GE-Proton

COMMANDER · Install pageInstall GAMMA

COMMANDER · Deck ModeInstall the game's runtimes from Deck Mode

COMMANDER · Play pageTest the game once in Desktop Mode

COMMANDER · SettingsAdd COMMANDER to your Steam library

Steam · Desktop ModeSet the Deck Mode launch option

Game ModePlay from the couch

Deck Mode controls

If something goes wrong

Why the Steam Machine needs extra steps

Uninstall everything

COMMANDER · UtilitiesRemove the game with Full Uninstall

COMMANDER · Play pageRemove GE-Proton (optional)

SteamRemove the Steam shortcuts

KonsoleDelete COMMANDER, its settings and its menu entry

KonsoleDelete the Wine prefix and the empty folders

KonsoleRemove umu-run, winetricks and Protontricks

KonsoleDelete your save backups (optional, last)

System Settings + KonsoleTurn sleep back on and check nothing is left