Works out of the box
Videos don't play. Otherwise great out of the box

gamemoderun %command%
Out of the box, the videos in the campaign don't seem to play. GE Proton 9-25 (or any other version, probably) fixes that.
Videos inside game are not working.

Runs perfectly under Linux
Zero issues, just runs out of the box as expected
Works perfect.

gamemoderun %command%
Had no issues playing the game, even with very large enemy groups
Very pleasant to just play without tinkering!
Fonctionne aussi bien sans proton-ge
gamemoderun %command%
Le jau plante rarement avec alt+tab, heureusement qu'il y a des sauvegardes automatiques
Les cinématiques ne s'affichent pas tout le temps, les images du tutoriel du jeu ne sont pas lisibles
Game freezes when fullscreen and losing focus. Borderless window mode works great

Crashes a few seconds after starting a game
The menu and music work fine, the game loads and then quits out.

It crashes after about 5 minutes of playing
Game crashes after about 5-10 minutes of playing
Crashed once after alt-tab, but didn't any of the other times I tried
7.1-GE-2 GloriousEggroll
Video playback in the tutorial and campaign shows either nothing, or the standard video test pattern. You hear the audio, but no video.

DEMO REVIEW. Playable but with minor issues.
Game could successfully Alt+Tab and release cursor into a new windows/screen and would cause game to minimize. Once minimized the game would not reopen and had to be shut down via System Monitor or terminal.
The tutorial mission seems like it should have some video lessons but would only show the SMPTE color screen bars.
Game was reviewed during the demo phase and approximately 1 month before anticipated release. There isn't too much content to test and review but should be somewhat representative of basic Linux playability.