Hello @legluondunet, this looks like it's not a Proton issue. The game itself is marked windows only, but "The 7th Guest - Legacy Edition (English Voice-Only)" DLC has a linux launch config. Please go to the game's properties and enable the per-game Proton override.
That could explain why the game is marked as "Native" on protonDB and why it is indicated on SteamDB that the game supports Linux and MacOSX.
Once I forced the use of Proton (4.2-2) the game fully installed but...didn't launch.
I joined you the log file.
steam-1044340.log
err:mscoree:CLRRuntimeInfo_GetRuntimeHost Wine Mono is not installed in the log points towards #18.
I would like to install .NET 4 with protontricks, when I launched the command:
$ protontricks 1044340 dotnet40
the setup .Net window said that .Net 4 was already installed.
So I choose the "repair install" option and .NET 4 reinstalled OK.
I can now launch the game.
another issue: I don't know how to change interface language and the game does not use my steam language settings.
Did you change something? The language is now correct, same as my user session. I can not reproduce the language issue.
other bugs:
Nothing extracted yet.
Compatibility Report
System Information
https://gist.github.com/legluondunet/8570a65372c3f7b9fea9c365c449cc59
I confirm:
Symptoms
The game does not download, only extra contents
Reproduction
click install, only 300 Mo download, nothing in the aim game folder, only the "extras" folder downloaded correctly.