Confirmed.
Distro: Linux Mint 19 Tara
Processor: AMD Ryzen 7 1700
GPU: GTX 1070, Nvidia proprietary driver 396.54
RAM: 32GB
Kernel (custom) - 4.17.14 (optimized for Ryzen)
Resolution: 1920x1080
Proton 3.7-3
I'll third that. Works great.
https://gist.github.com/supashang/6050de4e5ed8854f58d7152521048170
I completed this game with a total playtime of 107 hours. Less issues than on Windows in fact,, so Proton is actually the better way to play this game compared to Windows 10.
On protondb the game has a "platinum" rating:
https://www.protondb.com/app/214170
The game runs out of the box with Proton 5.13-4. No tweaks necessary. Integer scaling (WINE_FULLSCREEN_INTEGER_SCALING) also works without issues.
proton 5.13-4x1 2020-12proton 3.7-3x1 2018-08proton 3.7-4x1 2018-08WINE_FULLSCREEN_INTEGER_SCALINGx1 2020-12
Distro: Ubuntu 18.04
GPU: GTX 980, Nvidia proprietary driver 390.48
Resolution: 2560x1440
RAM: 16GB
Proton 3.7-4 Beta
Works perfectly. Can't find any issues.