The multiplayer feature in TRON Run/r is currently unavailable, but it may be added to the game in the future. In the meantime, you can compete against your friends in Duels. Duels allow you to challenge your friends to beat your top score in a level. If your friend is successful in beating your score, you'll have the opportunity to play the level again yourself to try and top their score. A Duel can go back and forth as long as the players involved continue to surpass each other's time.