This was fantastic!
You have an amazing, imagination, i like the depth of the background, and yes i noticed the detail in the background of the Buildings were manually animated to give that 3D depth.
My favourite bit was the blonde girl who turns around and watches the Skate boarder, that alone brings interactive awareness to the surroundings making it known that the background and the people are not just cardboard cut outs...
The scheme you used in this animation is somewhat complicated but that's what i admire about it the most.