1) Since I read the description, I could tell that the color changing was supposed to be the passage of time, but I don't think I would have if I didn't. I would try to add some other sort of visual indicator, like a clock, that shows it as well.
2) I think the thinner road is actually perfect for a game like this. Just because you have the whole screen to move doesn't mean that you have to use it, and sometimes limiting player movement is a good thing.