Split Screen (Serious Sam: The First Encounter)

The question is about the game mode for two or more players on the 1st computer "Split Screen"

when playing in two, the screen is split horizontally, but at the edges of the screen (on the sides), there is a black space, is that how it should be? or can you make the picture fill the entire screen ??

Here's how I have - http://ipicture.ru/Gallery/Viewfull/2298349.html

and is it possible to change, when playing in 2 people, the division of the screen - horizontal or vertical division ??

Thank!