You play multiple rounds until someone reaches 500 points. In Uno Express: The game ends immediately when the first player empties their hand. That player is declared the winner of that "Express" round.
In a 5-minute game, the final two players will clash quickly. Save your Wild and Wild Draw Four cards for when you have 2-3 cards left. Changing the color to one you hold, or slamming a +4 on the player before you, is a winning move. Uno Express Rules Pdf
For those who want a more detailed explanation of the rules, here is a step-by-step guide to playing Uno Express: You play multiple rounds until someone reaches 500 points
: You must shout "UNO" when you have only one card left. If another player catches you before the next player starts their turn, you must draw two penalty cards . Action Cards & Their Effects In a 5-minute game, the final two players will clash quickly