The reason why teachers say not to do all your...
work at the last minute is that it will never been the same calibur as something superb. It's a good game. Very fun, may be slightly addictive; however, there are some glaring flaws/improvements that could be made.
1. No, introduction of new levels. This is annoying. I don't know whether I'm playing on level 1 or level 6.
2. Do somethings with the graphics. So, I expect roads, grass, etc. to be not bumpy and all that. Unfortunately, they are.
3. Many games, tend to have power-ups, and other bonuses. May be even alternate routes to end up at a conclusion of a course.
4. Show that you are at a conclusion of a level. It needs decor.
I can go on and on...but I don't know if this would be any help for you, unless you put some thought. It's a good framework, but there's more to be added to make it a great flash game. Henceforth, I'm saying, it's good, but it could be better.