If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
You drive the "Riprage", a monster truck, through your city, that has been devastated by a catastrophe. Roads are no longer straight and are full of obstacles. Jump over them by making a good speed, so that you can launch yourself. On your way you might meet traffic robots, that have no use any longer, now that the city has been devastated. So you can run them down, in order to earn points. You also obtain points by running down lampposts, phone booths and casks. The earlier you reach the end of the level, the higher your score will be. You can also increase your score by performing stunts.
Up / Down Arrow Keys - Move Forward / Backward.
Left / Right Arrow Keys - Lean.