Applies temporary host optimisations (CPU governor, I/O and process priority) for the game's lifetime. The bare word does nothing — Steam needs the wrapper form.
Proton-Deck
Feral GameModeAdded Jun 29, 2026Last checked Aug 16, 2026
Safe
-screen-widthCopy
Override the screen width (Unity games)
Effect
Must be an integer from a resolution the game supports. Pair with -screen-height; alone it can leave a mismatched aspect ratio.
Example
-screen-width 1920 -screen-height 1080
Display
Unity EngineAdded Jul 8, 2026Last checked Aug 15, 2026
Safe
-screen-heightCopy
Override the screen height (Unity games)
Effect
Must be an integer from a resolution the game supports. Pair with -screen-width.
Example
-screen-width 1920 -screen-height 1080
Display
Unity EngineAdded Jul 8, 2026Last checked Aug 15, 2026
Safe
-popupwindowCopy
Run in a borderless window (Unity games)
Effect
Creates the window as a dialog with no frame. Not supported on macOS.
Takes exclusive or borderless. Windows only. The flag alone does nothing — the value is required.
Example
-window-mode borderless
Display
Unity EngineAdded Jul 8, 2026Last checked Aug 15, 2026
Safe
-force-openglCopy
Force the legacy OpenGL renderer (Unity games, legacy builds)
Effect
Windows only. Selects Unity's LEGACY OpenGL backend, not the core profile — use -force-glcore for that. Builds made with newer Unity versions may not carry the legacy backend at all, in which case this has no effect.
Draws FPS, frame timing and CPU/GPU load over Vulkan and OpenGL games. The bare word does nothing — Steam needs the wrapper form.
Proton-Deck
MangoHudAdded Jun 29, 2026Last checked Aug 16, 2026
Safe
How to apply a launch option on Steam
Open Steam and go to your Library.
Right-click the game and choose Properties.
On the General tab, find the Launch Options field.
Type or paste the option (e.g. -windowed) into the field. To use several at once, separate them with spaces (e.g. -windowed -novid).
Close Properties. Steam saves automatically, and the option applies next time you launch the game.
To remove one, reopen the same field and delete the text. Options are game-specific; an option that helps one game may do nothing (or misbehave) in another.
Worth knowing: a launch option can break a game's rendering, reset local settings, or trip anti-cheat in multiplayer. Read the description first, add one at a time, and treat anything rated above Safe as a deliberate experiment.
