Managed to work it out, with the assistance of the Steam’s linux guide author. Here’s what’s necessary:
- download all the necessary files from the classic installers section (see pics #1 and #2), including the patches you have purchased, if any, for the patch version you want (supposedly, the latest one)
- follow the Steam guide but, instead of selecting the Steam installer, select the game’s installer
- when you get to the part that chooses “Steam.exe”, choose “Grim Dawn” instead
- you’ll get a bunch of errors during the installation process, such as the one from pic #3: click ok in all of them
- once finished, click exit
- skip from vcrun2015 part, because the game installs it for you, until optimization part, because you’re not installing Steam’s version
If you have no DLCs, you have finished and can now start the game
If you have DLC(s), you’ll need to add those:
- open PlayOnLinux
- click Configure
- select game (left side)
- click Miscellaneous Tab
- click “Install an .exe in this virtual drive”
- select the installer
- follow instructions
- click exit once finished
- repeat, if more then one DLC
- you can now start the game
There’s a bit of bad news, though: whenever there’s a new patch, you’ll need to erase the virtual drive in PlayOnLinux and re-install the whole thing, after you download the necessary files from GOG. I tried to upgrade to 1.0.6.1 from 1.0.6.0 and it didn’t work.
I think i didn’t write anything out of order in these instructions.
Pic #1
Pic #2
Pic #3