For Evil West players, since the widescreen is not supported for the game and the image is simply being zoomed in and fills the screen, this guide will help you out.
How To Fix
1. Navigate to the configuration file(s) location:
Steam Play (Linux): <Steam-folder>/steamapps/compatdata/1065310/pfx/
2. Open Engine.ini.
3. Add the following at the end of the file and set it to read-only:
Have fun slaying 😀