Serious Sam
From PCGamingWiki, the wiki about fixing PC games
Add custom resolution:
In this example we will change the resolution to 1680 x 1050:
Go to your Serious Sam install directory, open the Scripts folder and open PersistentSymbols.ini. Then change these variables:
persistent extern INDEX sam_iScreenSizeI=(INDEX)1680;
persistent extern INDEX sam_iScreenSizeJ=(INDEX)1050;