Wow! Nice research Jan, that's quite a bit of inspiration. I know you all have been curious to see my machinations in flash and here is a shot of the work unfolding.
It has been a difficult task to work in a very, very narrow range of gray colors. The idea is to keep the user in the dark visually, but use a great deal of sound cues to simulate environment.
There will be another interactivity trigger that is being worked on as I report. The basic concept is that there will be small points of interactivity that must first be "discovered" in order for the user to begin to understand the environment. The reasons that larger ones were forgone is because if the "hit zones" become too large then the subtlety is lost.