Distro: Linux Mint 19.1 Tessa (64 bit)
GPU: Vega 56
Driver/LLVM version: Mesa 19.1.0-devel/9.0.0
Kernel version: 5.1.1-050101-lowlatency
Proton version: 4.2-3
Game is playable, but cut-scene videos are skipped. Also the game launches behind the desktops taskbar like this:

Need to alt+tab between desktop and the game to fix it.
media_info.txt
steam-6830.log
system_info.txt
In the log I see
19994.801:0027:0028:fixme:quartz:AsyncReader_QueryInterface No interface for {2dd74950-a890-11d1-abe8-00a0c905f375}!
#1464 The game uses quartz and the videos (stored as .pop files) are: WMV, VC-1 + WMA
I disagree: the game randomly crashes early in the first tutorial mission.
So I've tested this game with Proton 9.0-4, 10.0-2 (RC) and Experimental (2025-07-11). My findings:
Proton 10 logs: steam-6830.tar.gz
Specs:
proton 9.0-4x1 2025-07
This can easily go onto the whitelist. Works as intended.
My Sytem info:
https://gist.github.com/Zero86Sk/d629f657c1ae861c36657cdf238a7765