Get a lot of high power projectors, creating 3d models of the building, animate parts of the 3d models, and project it into the 2d plane of the building. See this video for additional reference. http://www.youtube.com/watch?v=jDHfa03XzaM
I viewed it on Vimeo, rather than Kotaku, and the commentary there was much higher quality. I did wish however, that there had been a "no flash" policy during the filming, as the constant camera flashing was quite distracting.
No flash policies seem consistently ignored, often by people who don't know how to manipulate their cameras to turn the flash off, so I wouldn't hold hope that this would make a huge difference. (People still go around museums constantly using their flash, so I don't see why this would be any different).
