The result, then, is the illusion of a world of unlimited choices.  "I guess I'd say we came closer than any other game I'm familiar with (and kudos to the team for that) but not as close as I would have liked. I mean, it just isn't possible, or I don't know how, to give players complete freedom."

One of the desirable compromises of player freedom, however, is a linear story.  A narrative which branches into multiple stories may offer more choice, but in the end, the single through line, or as Spector calls it, "a string of pearls", is the one with the most impact:

"We made one very tough but, ultimately, critical decision early on," Spector says.  "That is, we decided to go with a completely linear narrative.  The earliest incarnations of the plot had two or three branch points, but we eventually ditched 'em.  The shipping version of 'Deus Ex' is unashamedly linear.  But what that meant was that we knew exactly the state of every player's game at every critical plot point.  And that meant we could tell a cool story."

So while some players will accomplish JC's tasks with wholesale destruction, others will prefer Thief-like stealth, or a salad bar of combined approaches:  "That also meant that, as long as all players GOT to the same plot points at the same time, which they inevitably would," says Spector, "we could give them a LOT of control over how they got there... We just didn't care if they killed everything that moved or killed nothing to accomplish a goal. We didn't care if they picked a lock, talked someone into giving them the key or blew the door up. All we needed to know was that they were going to get through the door. See what I mean?"

Deus Ex

I think so.  Though I have to wonder how Spector's ideal to allow as much freedom in player interaction as possible will work, and if it can work without compromising the game world's basic plausibility.  If you're confined to a single core story-line, I ask him, can you really accomplish the same ends with totally different behavior patterns in a way that's believable?   After you leave a high-security building a demolished wreck, for example, in real life, that usually leads to a full-scale manhunt by authorities, and vastly increased security in every other top-secret facility.

"That's what common sense would dictate," concedes Spector, "And in the world, that's probably what would happen.  But in a game we have to be more forgiving than that, so what happens is, if you go in guns blazing, and the door blows up, the bad guys show up."   You can try and fight your way past them, or hide and wait for their search to end -- which it eventually will.  "It's unrealistic, but it's good gameplay."