The Wizard (1989)

Brothers Corey and Jimmy Woods are being separated by their parents' divorce. Jimmy is a mentally-unstable boy who has had problems ever since his twin sister died at a young age. One day, Corey discovers that Jimmy has a natural talent for playing video games. He is one of the best around, and the two journey to the West Coast to compete in a video-game championship, but along the way, they must avoid the adults who are trying to take Jimmy away.