Nice take on the theme, and I like how the name accurately represents it.
I liked seeing the shadows chasing you, so you know you're only one step away from death. However, to improve that, as others have suggested, it would be good to see some debris on the road, if you stumble you're almost certainly going to get captured by the horde .
While I liked the music, I'm not sure it fit the type of game, but others may feel different.
I think it would also be good if you could pick up random weapons from the road as you're running, like a baseball bat, and take a swing at zombies running in your direction.