A scrolling background could defiantly fit this scene. I think you had it scrolling too quickly for a majority of the video though. In my opinion, it was best at the scroll speed of 50 as a lower speed fits the more relaxed mood of the rooftop theme. I think animating the cat would be a good idea but I wouldn't recommend adding sound effects here as I think that would take away a vital element from the mood. Overall, a cool experiment that defiantly got my interest.