You start with 3 cars:
There are 6 episodes in the game, and each of these episodes have stunt challenges, mini-games and races.
When you win a race, you unlock a wheel type. When you win a game break you unlock different decals. After the end of the episode, depending on your score, you unlock a car. If you finish in second or third, you unlock a car. By finishing first, you unlock another car.
When you finish all episodes in first, you unlock a gold version of one of the in-game cars.
List of cars featured in Hot Wheels: Stunt Track Challenge: