upload his config.exe somewhere? GOG version of this file is outdated and contains no windowed mode.

It works, thanks!

One question thou, are you able to use any other resolution than your monitor's native in windowed mode ?
I haven't been able to do so, of course its normal for borderless windowed, but i've been trying to run the game at lower resolution inside the window :(

The windowed mode seems to be bugged. It opens a fullscreen window whichever resolution you choose. if your game crash with an assert failed error when trying to reduce the window, try launching the game directly from eadorMOTBW.exe instead of going through the launcher. Note that it reopens fullscreen window at next launch (does not retain the window size).