I do not wish to spark discussion about platform support and such.
I just wish to notify the few people to whom it is relevant, that the current build (closed beta VI) runs out-of-the-box using Proton (3.7-8) on Steam.
While I haven't compared the performance to running normally yet, so far it feels like it runs perfectly.
Only issue I have come upon thus far, is that zooming in the Geoscape is... Odd.
Seems like it's not registering the input most of the time, so you have to scroll for a little while before you get anywhere.
Including the issue here since it's likely caused by compatibility.
