Not sure about the theme but you nailed the constraint. At first I thought the city was empty and half expected to run into a heard of walkers. Then I found Jenny.... we are married now.
Cheers mate. I was under the illusion that the theme was a minor extra rather than the centrepiece, and coupled with the 2 day time constraint it makes my implementation look a bit lacklustre. I will not take the theme lightly in the future!