
PROTON_USE_WINED3D=1
Installation of MFC42 is required.
Playing the GOG version through heroic, installation of the windows component "mfc42" is required to get to the launcher, and adding "PROTON_USE_WINED3D=1" in the environment variables is also required. Heroic makes installing the mfc part very easy, just click on the winetricks button.

Нужен префикс mfc42
Включил вертикальную инверсию
Уменьшил потребление ЦП.
В настройках нужно выбрать оконных режим во весь экран. В полноэкранном картинка по горизонтали вылезает за края.

Works on OLED at 90fps with dips. Can be a stable 60-70fps. Looks amazing and plays exceptionally well on the Deck.
Launcher needs manual interaction (e.g. holding Steam button and use mouse). Simply using touchscreen to select "Start" will result in the launcher closing and returning you to gaming mode. You MUST hold steam button and use mouse.
The game launcher requires you to hold the Steam button to use the mouse to start the game. Using touchscreen wont work and will return you to gaming mode.
Just make sure to hold the steam button to use your mouse in the in game launcher.

Very little extra work needs doing, if you use protonup-qt and install latest version, it's up and running real quick!
Disable HBAO through game's launcher. After that you can launch without launcher.
Game would not launch. I did zero tinkering. I would say out of the box this does not work at this time. 12/19/2023

Game doesn't start with Proton 8.0-4
D3D11 rendering API error
Tried "protontricks 910830 -q --force mfc42 win7" without success.
Tried with multiple Proton versions including Proton Experimental, Proton 4.x, Proton 7.x, GE-Proton7-30. Result is always the same: launcher partially runs, but dropdowns and menu items do not appear until mouseover. Launching the game throws an error:
OGRE EXCEPTION(3:RenderingAPIException): Failed to create Direct3D11 DXGIFactory1 in D3D11RenderSystem::D3D11RenderSystem at c:\rg2\trunk\externals\ogre_1_9\rendersystems\direct3d11\src\ogred3d11rendersystem.cpp (line 3734)
Disable HBAO in launcher to get 60 FPS
Launcher needs manual interaction (e.g. holding Steam button and use mouse)
Audio seems partially too loud when shooting weapons
Needs tinkering, either by installing mfc42 manually (e.g. Protontricks) or selecting GE-Proton7-27 (which includes a protonfix) In the launcher it helps to disable HBAO to get 60 FPS instead of 26 FPS
Tutorial: https://youtu.be/6sNg_fy5KOI
protontricks 910830 -q --force mfc42 win7

Don't want to start
Tryed out some Proton versions (7.1/7-10/7-20/5.1) and also the protontricks mentioned, no cigar.
mfc42
To run, install protontricks from the Discover store. Run that, choose the game, then go through the GUI to add "mfc42" binary to it. Went from not launching to fully playable.
protontricks 910830 -q --force mfc42
Had to force Steam Input to: "On" for Controller to work
Runs great. I was not putting the proper configs into ProtonTricks. Make sure there is a -- in front of force.

Game crashes after launcher.
Proton Tricks command did not work for me.
protontricks 910830 -q --force mfc42 win7
protontricks 910830 -q --force mfc42 win7
Works great after running the protontricks command; protontricks 910830 -q --force mfc42 win7
Install mfc42 and everything works!
The game may take a little time to start, you may get a "window not responding screen" at first, click wait and it's fine.
protontricks 910830 -q --force mfc42 win7

Installs, does not launch
Crashes silently after launcher.
Works well, but only after installing protontricks and figuring out how to install the mcf42 dll's
Installed Winetricks and Protontricks, and then installed mcf42 within protontricks.
Game installs and launches. The options window will open but when you try to start the game it fails.

Game crashes almost immediately on launch. No screen change.
Steam Log -> err:module:import_dll Library MFC42u.DLL Not sure how to load MFC42u.DLL file in proton. Perhaps someone could figure out how to load it.

Game install, launcher starts, can't get into game
Tried with default 5.0-9, and with Proton-5.9-GE-3-ST Proton-5.9-GE-5-ST Proton-5.9-GE-6-ST. Also, launching without the game launcher just leads to it crashing. Reported on Proton's Github page, will update the report if something gets fixed
mfc42