Small screen thooo help

[NanNobody]

If anybody please help. I got a new tablet but when I open a game it just not on ll screen I search everywhere for answers but none. But when I touch the black screen, the small screen works and response e problem its just idk its just small for real help-

 

[kevincalori]

what is the brand? have you tried to uninstall & install again of the gamming app.