

EAC error, can't play multiplayer
Stock Proton works fine but gives no steam overlay. GE proton enables the steam overlay.
Regularly kicks you out of matches the first time launching the game each session with an EAC validation error, but will no longer kick after restarting the game

Update to my previous report: got the game running perfectly on Fedora, see Proton's github here for details.
No issues

Stuck on Initializing before the game opens a full screen window
Tested on Proton 8.0-5, 6.3-8, experimental, hotfix, GE-Proton9-2
see Protons Github for full report and image.
- Proton EasyAntiCheat Runtime is installed in Steam.
- I have tested on Proton 8.0-5, 6.3-8, experimental, hotfix, GE-Proton9-2
- All proton versions encountering same error
- Also tried Steam Big Picture Mode, still encountering same error
- Steam overlay is disabled to try to remove possible variables

MANGOHUD=1 %command%
Game would not launch unless I downgraded to proton 6.3-8
Game ran fine once I got it to actually launch. I tried with versions 7.0-6, 8.0-5, 9.0 (beta), and experimental. Steam would try to launch the game, it would run for about 1s before automatically closing with no errors. Setting to 6.3-8 allowed the game to finally launch.
Works fine
gamescope -f -e -w 1920 -h 1080 -W 1920 -H 1080 -- %command%
Lag when vault opens and when the briefcase is picked up.
Easy anticheat causes steam overlay to not work, which means custom crosshair mods are unavailable (and they are 100% necessary IMO). It also breaks the in game cosmetic store, but that's not a huge deal.
Lag when vault opens & when briefcase is picked up, but that's about it.
Steam overlay doesn't work at all, no idea why. Bottles doesn't fix the issue either. The game is 100% playable without the overlay though, BUT it means you can't replace the absolutely horrific crosshair (plain white dot), since all mods use steam overlay. It also makes the in game cosmetic store unavailable, but that's not really an issue for me.

Manually added steam_appid.txt to the game's install folder
Constant EAC-related disconnects
As it stands, I am unable to play Deceive Inc on my Fedora install.
I have tried standard versions of Proton (stable/experimental) as well as GloriousEggroll, to no avail. Regardless of which version I pick, I keep getting kicked out of lobbies with the following error:
"EAC Validation Error"
At best, I can play in a lobby for 1 - 2 minutes before the before the above error rears its head, but more likely than not it happens almost instantly after finding a session.
The stability has improved a lot recently, and apart from ocasionally having to restart the game, it works pretty well
Sometime the game would just load without textures, or textures would break if you changed settings mid game. This has been getting less frequent though
When I had an XBOX controller plugged in, even if I wasn't using it, my game would get super stuttery every time I fired a gun or changed disguises. Unplugging resolved the problem
Ocasionally the game wouldn't start. Hitting stop and trying again usually fixed this issue
Sometimes the game would say client integrity check failed. Restarting the game fixes this
I only tried Proton Hotfix because of the previous reports here and since it is a frequently updated multiplayer game with EasyAntiCheat. I have not tested other proton versions.
Really fun game, had a hiccough where the servers didn't allow Linux players but that has now been resolved.
Really fun gameplay, only downside is the newest patch (Dated 20 April 2023) killed online play, the Dev team is already looking for a fix.
After the 1.06 Misery Empire update, the game is now unplayable online because of EasyAntiCheat kicking me out of every match.
Anti cheat error on latest update. "Device Integrity Error"
PROTON_USE_WINED3D=1 %command% is needed to even launch the game since there is an error popup when you run the game.
PROTON_USE_WINED3D=1 %command%
Most of the textures are black or some inverted color.
Slight input delay.
Stutters while moving, shooting.
PROTON_USE_WINED3D=1 %command%
Without the ingame "d12 (experimental)" option enabled the game doesn't show some textures.
With that option enabled the game sttuters a lot.
Game runs very well even at max settings on my machine, controls very smoothly without any input delay issues.
Firing and the cover mechanic cause huge audio crackles with default Proton. Using ProtonGE fixed it.
Firing and the cover mechanic cause huge frame drops with default Proton. Using ProtonGE fixed it.
Game runs like native in every way except for frame drops and audio issues when weapons are fired or cover is broken/recovered. Using GE fixes the frame drop and audio issues.

Runs amazingly on the Steamdeck highly recommended to try it!

I toltally suggest anyone who has a Steamdeck to try this game out on it, it runs incredibly amazing!