The antonyms for "plays the game" could be "cheats," "breaks the rules," or "bends the rules." These words all suggest a behavior that is dishonest, unfair, or unethical, and they imply a lack of respect for the spirit of the game or the competition. When someone cheats, they gain an unfair advantage over their opponents, and they undermine the integrity of the game. When someone breaks or bends the rules, they show a disregard for the rules of the game, and they may cause harm to themselves or others. In contrast, someone who plays the game with integrity shows respect for the rules and the competition, and they enjoy the satisfaction of fair play.