Players tried everything: tweaking the game's settings, updating their graphics drivers, even reinstalling the game. Still, the display mode remained stubbornly fixed, forcing them to play in a suboptimal resolution.
You can also try adding -safe to launch with minimal video settings. 4. Graphics Driver and DPI Settings serious sam 3 cannot set display mode
Share it with your co-op buddies so they don’t rage-quit before the first level loads. updating their graphics drivers
Alternatively, you can edit the INI file directly: even reinstalling the game. Still