The Twist: The main twist occurs early: the Warriors are framed. The tension comes from the fact that the entire city believes a lie. The resolution occurs when the Riffs (the most powerful gang) finally learn the truth from a witness.
The Ending: The Warriors reach Coney Island, only to be cornered by Luther and the Rogues. Swan fights Luther and disarms him with a knife throw. The Riffs arrive, not to attack the Warriors, but to capture the Rogues. The Riffs acknowledge the Warriors with "You Warriors are good. Real good." The final shot shows the Warriors walking along the beach at sunrise, safe at last, while the Rogues are swarmed by the Riffs, implying their demise. The ending validates the Warriors' code of honor and endurance.