http://video.google.com/videoplay?do...interview+prey
An interview from 1998 with one of the developers behind Prey who showcases and narrates a games journamist through Prey as it was at that time. Very, very impressive technology for it's time and if they just had released that game the same year or year after, it would have pwned Half-Life totally!! - or at least it would have been standing in history together with Half-Life as one of the most greatest FPS for it's time
But that's not the way things worked out and it's hard to see why. In the interview he actually tells us that they 80-90% done with the technology development, and the levels, weapons and indeed the technology seems to be in a pretty late-phase of the development. Furthurmore in the original Prey you could create your own portals just like in Portal! It's a real shame that they dropped this idea as Prey "just" went to be that normal good FPS and not a revolutionary and truly innovative and fascinating FPS it had the potential for - A pity but that's the way things work out sometimes