Works just fine, but do note the weird issue with the Linux version!
IMPORTANT: This game actually has a native Linux version, despite not being advertized on the Steam store or in the Steam client. If you check SteamDB, you'll notice that the game has a depot for a Linux version, and that is the one that will be installed if you install the game on Linux. I did some digging, and it seems like the developer just provided a basic Linux version (as this is a Unity based game), but did not have enough confidence in its ability to support that version to advertize official support. I lost about an hour of deep confusion to this.
If you want to use the Windows version, you need to force compatibility though the properties window. I ended up playing the Windows version through Proton because DXVK maintain the proper aspect ratio on an Ultrawide screen (for which this game does not have the proper support), while a native OpenGL application usually does not and I still haven't found a fix for this.
I did not really encounter any issues with either version.
Too slow to load (ok), clear flicker whenever camera is moved (not ok).
Horizontal flicker in the middle of the screen, from edge to edge whenever moving the camera.
Game starts up fine but one has to start it twice. Loading saves and maps are incredibly slow.
Be aware: if you are running this (Unity Engine) game in windowed mode, do not resize the screen, accidentally or on purpose. The fonts will disappear. & some 2D screens, too. Otherwise, the game runs perfectly out of the box.
Played about 15 turns (1-2 hours) without a problem.
Flawless out of the box.
Runs perfect (maybe native?).
Booted up the game and started a campaign, tested some stuff and it all seems to be working perfectly. No performance hit, lag, etc. Runs as if it was ran on Windows.