I like to think that the atmosphere is at least partly my doing, although sometimes I feel that my photographs of buildings are merely repeating ideas which found expression long ago in the mind of the architect. I think avoiding that is why the people are so important - just as a figure in a landscape can direct the viewers response beyond the scenery.
Opressiveness is one element, but I also wanted to show the security guards as reluctant angels, leading an exalted but tedious life at the top level of all that grandeur while life goes on elsewhere. I can't show it on the web, but in addition to the pair on the gantries there are two more peering over one of the parapets on the left.
Sticking with friendly colour is deliberate. It is a huge barn of a building, but the sunken base level hums with life, and it seems to be a popular place to break out the bento box come lunchtime. Shown larger, it's really obvious that the guard's uniforms are royal blue, which adds a touch of whimsey and stops things getting too opressive. I agree that it would be possible to make an interesting print by emphasising the Metropolis aspects, but that's not at all how I felt when I was there. Perhaps I'll change my mind if someone posts a suitably-doctored B+W example - feel free to help me see.
Tony, I've always loved being high up, but I am superstitious enough to prefer even crumbling and rotten rock to most man-made structures. The walkways are pretty wide, so it is possible to not-look-down. I'd definitely recommend the Forum as worth visiting for any Tokyo-bound photographers, especially as it is one of the very few things open on a monday. How it looks depends how you look:
Alternate viewpoints