With time, this idea evolved and grew into a very Doom-like scenario where one is hunting monsters through a pitch-black series of caverns and tunnels, and some of them are hunting you. There would be careful attention given to the sounds echoing off different surface types, and the clue noises that would let you know that another creature was in the area.
Of course, by the time you are working on something this sophisticated, you will need the dedication of a full blown sound engineer to get the modelling right, as well as the usual complement of level designers and game coders.
It would also help to have a catchy name. At one point I was calling the game 'Alone in the Dark', but that title has long-since been used elsewhere for a computer game, so I suppose a new name would have to be devised if anyone were to actually produce this.
The big issue that has prevented this being created up till now has always been the cost of production. I had always envisioned it as something the size of a walkman with high-quality stereo output. The trouble is that high-quality sonic modelling of an area is a fairly hefty computing task. Far more difficult than I ever realized back in 1980.
On the other hand, programmable walkman-sized devices with quality stereo output have recently become commonplace, as exemplified by the Apple iPod. Most of these devices can have additional software installed on them, so the prospect of writing audio-only games for them has become less improbable.
Now an obvious question might be: why not implement this on a desktop PC? In fact, until this moment the option hadn't occurred to me. When I first came up with this idea there were no stereo outputs available on PC's, nor were there any for many years after. I got used to thinking of the program as requiring some sort of dedicated hardware. Nowadays though most computers have sound chips and stereo output that could probably handle the computing load easily.
Of course, there's a big difference in user experience when sitting in front of a computer than when wearing a dedicated device, but it would certainly make sense to write and test a prototype on a desktop machine. That way you could demo it to a an mp3 maker as a possible item to bundle into their latest offering so as to make it stand out from the competition.
How well it would sell another question indeed. For most of my suggestions in these essays, I have a good estimation for how well some product will sell or be adopted. For this game, I have no idea. I only know that I would want to play it.