Room Zoom [Xbox]

Unlocking cars
To unlock other cars, you need to find three keys per level. When you begin a level, it is a good idea to find all the keys, then complete the laps. It does not matter what you place when you are looking for keys; take your time, and complete the level. If you do not complete the level and found all the keys, do not worry, you still get the prize. However to go onto the next level, you must place third or higher.

Unlock Fastest Car
In the level "Tomb and Gloom" you can unlock the fastest car by finding the three keys. When racing this through the first time, look for the keys and dont worry about where you finish. To advance later, however, you must place third or higher. The last key is hidden in a curtan draped off the ground in a decending matter (Just hop off the ledge onto the curtan.)

Easy Way To Find Keys
A good rule of thumb when finding keys is to elevate the view up off the car a ways. Then it is easier to spot the glittering of a key in the distance.