If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
In order to test the abilities of the new tractors that were created for the future, you should have an awesome race. You have eight incredible levels and you will be able to unlock five amazing tractors, each one performing better than the previous ones. Just make sure you do not crash during the race or that you do not run out of fuel. You have to be the first one to cross the finish line in order to win. Use NoS power to help you. Have a lot of fun!