


Tried proton 9.0, 7.2.2, 6.21-6, 5.0, 4.21, experimental and latest GE, all resulted in a crash. Plain wine worked flawlessly.
Native version works great.

Works out of the box
You may use the trackpad mouse at times to access some card defintions and other small details.
Limited framerate to 30FPS
You can increase the UI scale from the settings menu, which I highly recommend doing. Some text is still a bit small, but not illegible.
Griftlands has a lot of extra information about cards and effects that is shown on mouseover. I couldn't get some of this info to show via the gamepad inputs, so I had to use the trackpad as a mouse for this.

When launched with recommended Proton through regular steamos interface, I get Klei Slash but then a black screen
Just discovered it will launch from Desktop mode and work correctly.
Game works after disabling fullscreen in the config for the first launch, then toggling it on in-game
Had to disable fullscreen in config for first launch, then enable it in game
Running game natively, the game window was in fullscreen but the actual game only took up the bottom left corner of the screen and was completely unresponsive. Had to edit the file at $HOME/.local/share/Klei/Griftlands/steam-/settings.ini and changed "fullscreen=1" to "fullscreen=0". After launching the game with that setting, the game now was responsive but the mouse area was significantly higher than the cursor; as in, I had to click below where the buttons actually were. Toggling borderless window to on in the settings menu fixed that issue.
It's often frozen when returning from locked screen after long break. Beside that everything ok.
The latest version plays perfect, no problem, had also no problems on the other version, played a total of 15h with proton.
When changing from fullscreen to fullscreen-window, you need to restart the game, otherwise you can not switch to the other monitor

Game crashed (black screen right after launch) until I set Proton version to 4.2-9.
Worked perfectly the whole time that I've played
Works great out of the box, 1440p 144 Hz without issues besides the alt-tab thing
In borderless fullscreen, alt-tabbing on the same monitor is not possible
Fonctionne parfaitement sans aucun problème !
Works out of the box with current Proton 5.0-9
Game worked perfectly! No problems at all
Once you install extra packages from a PPA the game runs seamlessly with no bugs, at least windowed.
The game does not run OOTB on Ubuntu 18.04 or derivations of it (like elementary OS). To fix this you need to install packages from a PPA; instructions are given in the link I provided.
Runs beautifully out of the box, no tweaking needed. Didn't experience any bugs/visual artifacts.
perfact out of box
no issue

Game installs, but launching just gives a black screen
See title. If I force the use of Proton 5.0.9 instead of accepting the default, then the game installs, but launching gives only a black screen. I've waited up to two minutes and the game never loads. Eventually I have to force quit the application.

Unable to initialize the game
After moment of black screen "unable to initialize the game" error appears
Runs very well.
If you have a multimonitor setup, the game will capture your mouse in fullscreen mode. Other than that, it runs perfectly out of the box.
Runs great with no issues. Only one minor issue that is easily alleviated without tweaks.
The game doesn't release the mouse input while in fullscreen mode and attempting to ALT-TAB in a way that is compatible with GNOME on Xorg.
A simple workaround is to exit fullscreen mode (ALT+ENTER) before ALT+TABing or switching workspaces (SUPER+{PGUP,PGDN}).

Had the alt-tabbing issues others mentioned on 5.09, the Proton-5.9-GE-2-MF fixed that for me. Runs smooth.
Proton-5.9-GE-2-MF GloriousEggroll
Ran perfectly smooth at 144 fps (Capped at refresh-rate). No issues.
Alt-tabbing causes the system to freeze for a few seconds
Played the game for over 20 hours on the Epic Games Store through Lutris, so far playing on steam has been the same experience.