Hmmm... now there's something you don't see every day!
Red challenges get your attention. They require constant focus, good control and quick reactions; but they are still forgiving and leave some margin for error. Most have one or more spots where you have to get it just right to complete the lap.
There are no black challenges on 900FootAlien. (If you agree that a black challenge is one that requires absolute driving perfection at all times to reach the finish.) We have two reasons for this. First, they are seldom fun to drive. Second, they are really tedious to design and test because they are seldom fun to drive!