Thanks for the demo! I always enjoy such things and am always inspired by
others work. The four things I feel would most give a better game in this case
would be;

The cars need simple collision! This is above all the most distracting
visual challenge.

The wheels should spin, even if it is something simple in the wheels action
along the lines of; "if(car01.x > 0){my.tilt += car01.x*time;}".

The Track needs to be more than a constant curve (circle), create some curves
going both ways.

You could create a similar splash with a few photos off google, but I would
ditch the nfs copy.