
Works out of box.

Works well apart from 1 gamebreaking bug
The game seems to have an issue where when shooting with keyboard and mouse with a controller connected, fps drops down to just 20 momentarily. Sometimes it happens right after you load in, sometimes it takes a bit into a mission to occur. What fixed it for me was either 1) disconnecting the controller or 2) briefly interacting with the controller.
Older Proton versions did not fix the frame drop issue. I tried Proton 7 and I noticed no change, went back to Experimental. This is probably just a bug in either Mesa or the game

Works well, plays well.
Big frame rate drops when firing a weapon. Team mate weapons do not affect performance and the drop only lasted for the duration of the weapon animation.
I had a PS5 controller idle and charging from USB. The issue went away after using the controller, i.e. waking it up and pulling the right trigger. The performance remained stable after plugging out the controller.
It plays fine, but you might crash if the host alt tabs out of the game.

Works perfectly. Need two friends though. 3 player game.
No issues with running it. Need two friends though :(

No Linux-specific issues
It's a janky game, but that's the situation on Windows too. Multiplayer works fine, no crashes, performance is good.

Just works, including multiplayer
Played co-op with another person running the game on Windows. Worked flawlessly, no issues at all.

установить Proton UP-QT и скачать GE Proton 7-55 (до запуска steam) Перед запуском игры в steam зайти в свойства игры, выставить в принудительной совместимости GE Proton 7-55 и запустить игру (если с первого раза не запустится, перезапустить ПК и должно работать без проблем)

Occasionally (rarely) some sound effects goes mute for a while (most commonly in intense gunfights)
By default with KDE6 (latest version) settings didn't have full free view - had to disable desktop effects (unchecked all under Window management) to regain functionality
Steam Cloud saves went missing after switching Linux distros (from Ubuntu to Garuda)
With very few exceptions have happened crashing to desktop (in 70hr game time maybe 3 or 4 times)
Could be issues on my side with the operating system, but overall it's playable.
The system info here shows Intel integrated videocard, but the game actually uses GTX1050 mobile version (playing from laptop)

Worked great!
Played crossplatform with a friend who is using a Microsoft Store copy.

Played with my two sons who are local
Flawless experience.

Framerate drops make it almost unplayable. Every time I shoot the game freezes for a moment.
Framerate drops from 160 to 20 when shooting. No matter which graphic settings and DirectX version.
Multiplayer works perfectly
Tried different proton versions from 6 up to 8 and experimental, including GE. Tried gamemode, tried running in gamescope. Maybe a driver bug in mesa?

Sometimes the "Interact" button would not register. Could be a bug with the game although I have not heard this complaint from my Windows user friends.
Would sometimes crash mid-way through a mission
Sometimes the "Interact" button wouldn't register, meaning I could not refill ammo or interact with objects rendering the playthrough "Unfun"...the occasional crash too.
This does work and play fine on Deck but it is not without its issues.
The occassional bug ruins a playthrough and the monotonous gameplay, combined with lengthy missions, doesn't make for a top experience.
However it does what it says on the tin and can be fun in short bursts.
The game struggles with 60 hz/fps and i found the stutter annoying with 40 so i set hz/fps to 50 which is the golden middle-road in this case for me. Windowed fullscreen, FSR Sharpness 5, motion blur off, shadow quality low, texture quality medium, chromatic abberation off, anti-aliasing quality 2, ambient occlusion and screen space reflections off, DirectX 11, looks a bit ugly with these options, but at least stable fps between 45-50, rare drops to 40 in big fights with lot of enemies
Friends have occasional issues with connections, forcing a restart of mission (but not game). Unsure if related to Proton or Epic Online Services malware.
In conclusion, Epic should be treated like Carthage
A truly out of the box experience.
My save game with about 12hours of progress was seemingly deleted from Steam Cloud and I couldn't recover it. Steam Support claimed they can't restore cloud saves.
Works perfectly fine.
PROTON_ENABLE_NVAPI=1 gamemoderun %command%
Odd disconnect but this is possibly a game issue
No real issues. I did get a pause on initial load due to shader caching but it was quick to cache. I also had a radom disconnect from the game but the people I played through the whole campaign with also had the issue on Windows so possibly a game issue rather than Linux/Proton.
Game runs well, but you should consider running the game in DX12 mode (check settings), it really helps with freezes.
gamemoderun mangohud %command%
Lots of freezes.
Multiplayer worked perfectly.
No problems. Set graphics to around low-medium, maintained around a 30-40FPS in firefights
PROTON_ENABLE_NVAPI=1 VKD3D_CONFIG=dxr11 gamemoderun strangle --fps 143 --vsync 1 %command%
Co-op worked flawlessly.
There's no need for any tinkering, just press play. The game runs perfectly out of the box.

Works out of the box.
I did play coop with friends without any problems.
Ran out of the box and I didn't notice any performance problems. Coop worked without issues too.
Capped at 30Hz
Some framedrops, but still very playable.
Very nice to play on medium settings.
Runs great using DX11, no serious issues. Mangohud didn't work for me in DX11 so couldn't precisely test frametimes. DX12 mode causes around 10% performance loss, therefore I don't recommend it. In DX12, the frametimes were a bit jittery, jumping between 10-14ms constantly.
recommend performance tweaks mentioned for Deck. This game chokes CPUs with multiple enemies on the map.
due to not being able to not hold a locked 60fps the controls willbfeel sluggish as the framerate drops. I'd lock the fps for a smoother experience.
Use dx12, lock resolution to 800x500 in game properties (cpu needs the extra power), run FSR, lock tdp to 12-13 watts (cpu will throttle in big fights), set display to 45hz for a smooth experience.
Worked fine before the 1.0.4.100594 patch, now crashes at startup
I've tried different versions of proton (and proton-ge), I've tried all the launch options specified in this thread. Game crashes at startup. Game used to run fine with proton-ge and no special commandline tricks before the update on August 3 (1.0.4.100594) and now is a flaming pile of garbage ):

It's L4D but... ALIENS!
runs perfectly out of the box
Runs great but had to use dx11 mode to prevent crashing. Still crashes after EULA has been accepted with default launch options.
%command% -dx11
If you like this sort of game you will be happy, I didnt and got bored quickly but was able to play for a few hours without any issues.
MANGOHUD=1 DXVK_FRAME_RATE=30 gamemoderun %command% '-oldgameui'
It was laggy but only on the start menu once the game starts it is fine for me. And it isnt that bad in the game menu its just a little slower than normal to respond.
This is prbably due to the age of my computer, it was playable though with only a few stutters when in the missions (oddly, but when roaming around in the lobby it stutters a bit)
switched to 30fps mode and limited to 9w
Works well. No problems were found.

Hang-up/crash at the start loading screen with the EULA agreement
Game runs fine on dedicated GPUs, with Laptop APU (4500U and 5500U for example) the game crash/hung at EULA screen on startup...
Proton Experimental в настройках выключен кэш шейдеров
при запуске игры в оконном режиме, иногда нет возможности на стартовой странице игры нажать Начало игры или выход или параметры (сам курсор мыши виден и управляется в меню игры)
при запуске игры в оконном режиме, иногда нет возможности на стартовой странице игры нажать Начало игры или выход или параметры (сам курсор мыши виден и управляется в меню игры)
иногда вылетает игра при запуске миссии Единственный выход Задание 01. Подрыв
Works excellent!
After Recent Update game needed to be forced to use proton Experimental in steam game settings but once you have done this it runs perfectly
Force Proton Experimental

Black screen after season 2 update
Haven't been able to get to a title screen since the season 2 update. I can hear the menu music in the background, but no video displays. No success w/ Proton Experimental, v. 6.8-3, or the most recent Proton-GE. Will update if situation changes.

It's good overall but mostly depends from which card do you use. It can be improved.
Resolution is grayed out in windowed matching desktop resolution. It's full screen but cannot be changed. I had to sat 1080p on the display monitor in order to do a proper mirroring to my TV with the aspect ratio. It seems that for now, ingame resolution cannot be changed, included the other modes.
Frame rate could be improved. Downscale resolution to 85 with V SYNC on, solved for now.