Drive as fast as you can to the finish line. No, the time limit that is set is for the score and not for your truck suddenly exploding. If your truck crash then it one of your life will be one. You have 10 more lives to spare and when all that lives is gone then it is all over for you.
The game is controlled via keyboard, you need to drive your truck all the way through the finish line to finish one level. As you move on to the next level, you will find it tougher to finish the game because of the scenarios that you need overcome in the next level. Seriously, you can’t expect that it will be easier for you once you finish one level.