Nightmaster(1988)

Obsession is the deadliest weapon.

By day, Robbie (Tom Jennings) and his girlfriend, Amy (Nicole Kidman) are high school students. By night, they become top contenders in highly competitive simulated war games designed to test their athletic abilities and intellectual superiority. Although Robbie is a champion of the game, he soon realizes the extent of his instructor's fanatic extremes and the once-friendly game becomes real-life... and real life becomes a deadly game.