CarFight.io is a car war on the roof, you will have to fight with other vehicles, destroying as many cars as you get more points. And you can upgrade to a bigger, nicer, or upgraded car into a fighter. You will not be able to change levels if you are knocked out of the roof by other vehicles.
Start playing with everyone, choose a favorite car, use your left mouse to drag the car to your liking. Remember, do not go beyond the circle of the arena, otherwise you will be removed from the game and start over.