Your skills are great as usual Samantha, but maybe there are too many elements in the scene. Just one week is very few time to get a super shot with all this stuff to create.
A decent use of expert editing, but your light source is inconsistent throughout the scene. It's also odd to have a 25mph speed limit on what is obviously a freeway/highway, and the zombie on the overpass is very out of proportion.
Vision is very good, editing is pretty good, clean up the minutiae and you have a winner.
I admire the amount of work and processing that has made up this image, but for me it is too unrealistic, especially the character on the foreground [voted earlier].