The Wizard (1989)

Corey refuses to let his emotionally disturbed younger brother Jimmy be institutionalized, and the two run away together. They soon join forces with a resourceful girl, who notices that Jimmy has a special talent: he is a “wizard” at video games and can achieve the high score on absolutely everything he plays. Evading their parents and a sinister bounty hunter, the trio head for a climactic showdown at the national video game championships in California.