

PROTON_NO_XIM=1 %command%
see the entry of Namoria for Custom launch options. otherwise game crashes on trying to pick up items from crates

A fantastic game that runs without any major issues.
At the VERY end of the game, there's a video that plays summarizing your actions wraps up the story. This video does not play on Proton 9.0-3 or Proton Experimental. The sound plays for a little while but then freezes. I just reloaded the autosave right before the end and used Proton-GE just for this final video and the credits.
Unlike the previous two games in the series, this one runs on Unreal 4 rather than Unity. On my (pretty powerful) setup, the game ran maxed out at 3440x1440 at pretty much a locked 100fps. I don't recall any scenes where I experienced a significant dip.

PROTON_NO_XIM=1 %command%
As noted by others the game would freeze on picking up items from barrels and crates. The only setup that sidestepped this bug was the combination used by Namoria: Proton 7 + the PROTON_NO_XIM=1 %command%
launch command.
Works perfectly fine out of the box

I played this over the past few months, but playing now on version 1.5 is much better for controls and such.
However, I will admit that (depending on the person) some text may be difficult to read. I'm fine, but others may find it small.
Battery life was about 2 hours or so from 100% to 5%.
It is hard to read dialog texts in the game. I feel really tired after a couple of hours playing the game and reading dialogs.
Periodically, there are FPS drops during battles. However, as the game's battle system is turn-based, it remains playable despite the issure.
Combat sequences performance quickly degenrates to unaccectably barbaric levels (below 20) in a few turns. Everything else runs ok.
no matter the graphics settings, i would lose +/- 10 fps at every new turn start during combat scenarios. Gets under 20 fps within a few turns. Every other part of the game ran well.
i suspect it has to do with a memory leakage. my system is not being strained, gpu, cpu, etc are at acceptable percentages.
PROTON_NO_XIM=1 %command%
The game freezes when I try to pick up Greek Fir Jars from the crate. (Easily fixable, see my comment below)
The game runs out of the box, but I experienced a game-breaking bug: The game freezes when I try to pick up the Greek Fire Jars from the crate. Disabling XIM (X Input Methods) by adding "PROTON_NO_XIM=1 %command%" to the Launch Options for Expeditions: Rome in Steam fixed this. (My libx11 version is newer than 1.7.)
Overall, the game runs great; and, if you happen to experience this bug, it is easy enough to fix.

30fps option
Text is thin and blurry.
Videos dont render.
It worksat first glance. Didn't spend too much time on it
Crashed once in 90+ hours of gameplay really stable.

Runs perfectly no issues at all Proton 7.0-2
Game runs really well for my hardware all on high settings(1080p) 60+fps without any performance issue (did not compare it with windows). Its one of those out of the box expierences with no tinkering/no issues at all.
Seems like video did not work in older versions but they were playing fine for me. The game itselfs looks great and is really fun to play.

Videos not working
Game would freeze on startup with black screen unless Expeditions Rome/ExpeditionsRome/Content/Movies/Rome_MainMenuLoading.mp4 deleted
Runs fantastic out of the box
Missing cutscenes on Proton6.3-8 and Experimental Fixed on Proton 5.13-6
Had a consistent/reproducible freeze when trying to pick up torches from campfires on Proton 6.x & Experimental. Had to fall back to 5.13-6 Slightly degraded performance when compared to more recent versions

Enjoyable, other than the lack of video, and the game is not video-heavy.
As others have mentioned, the videos will not render. The audio for the videos as well as things like subtitles, etc still work fine. More an annoyance than anything else.
Runs flawlessly
Когда выходишь в меню или распределить навыки или в инвентарь, то игра очень очень начинает лагать, невозможно ничего сделать... но в самой игре, рпоизводительность кограздо выше, чем в меню
works great out of the box
Cutscenes are not displayed (colored placeholder image) with the default proton. This was fixed with latest proton-ge (proton7rc6-ge-1)

Runs great, it's just missing the videos for the cutscens
Cutscenes don't work (game displays test images instead)
Played demo and full game
Cutscenes are not displayed (colored placeholder image). Sound runs without problems during this time
Game can be played completely without further restrictions
Performance is comparable with Win 10. Cut-scenes missing might be a downer.
Cut-scenes did not show audio ok.