I saw the 4:00PM 3D showing at the IMAX theater near Time Square. It was a truly amazing experience seeing that city and then stepping out into a city that was different but not quite that different.
I had the same experience after seeing Blade Runner in the theater.
Our current world can be reasonably described as full-blown cyberpunk scene.
The scenes in the movie depicting the "real" Hong-Kong (i.e no CGI) were a shock for me. As a citizen of medium-size european city, I cannot imagine such inhuman cities exist for real.