Before you make any adjustments to the file,
Always make a copy of the file for easy revert in case of error;

What you need is to find one .ini file in game folder :

Which is:
DDrawCompat.ini



Open it with Notepad and put in your resolution at the SupportedResolutions line. Just like this :

SupportedResolutions = native

This way whatever hardware the user has will be covered



When you are done, use ctrl+s to save it.

At first you can only see basic resolution settings.

1. Click "Main Menu" and go back to Main Menu ;

2. Just type "hires" in the Main Menu to activate "High-Resolution Settings" ;

3. If you hear a "High Pitch single bell beep" sound, this means your "High Resolution" Settings has been revealed.

Just click settings and you will see the hidden settings ;

You can just use Shift+F11 in game to change scaling (and many more settings)

And here is the preview of the advanced settings: