Last night, I downloaded the Bioshock demo — 1.85 gigabytes! — and upgraded my graphics drivers, then gave it a try today.
It is the most beautiful game I've ever seen. The environment is incredibly detailed — and beautifully rendered Art Deco in style, at least in the demo.
It uses all the features of my graphics card, from what I can tell — from amazing water effects to spectacular lighting (check out the highlights on the different materials on this door, for example). And there are plenty of interesting character designs.
That said...
When I came to the end of the Deus Ex demo, I said, "I need to buy the full version of this game right now." At the end of the Bioshock demo, I asked, "Is that all there is to it?" It seemed to me that there was little more to it than going around a corner, killing the monster that jumps out at me, going around another corner, killing the next monster that jumps out at me, et cetera.
Other characters talk — a disembodied voice giving you goals to accomplish; threats from the founder of the undersea city of Rapture; nearby monsters raving aloud or talking to their "babies" — but you don't actually interact with them... other than by violence. Gameplay is pretty linear - you follow a specific route, and areas you're not supposed to venture into are blocked off by invisible walls.
Perhaps Deus Ex spoiled me - it provided numerous ways to accomplish goals, and in fact you could play it through multiple times with different styles (killing everything in sight one time, using stealth to get past guards another time), and the choices you made would impact game play later on.
Bioshock, for all its eye candy, seems to be just a twitch game. With all the amazing work they put into the visual aspect, the actual gameplay is somewhat disappointing. (There is one thing I dislike about the graphics, as well: character "lip-synch", when it appears, is nothing more than the jaw moving up and down; the lips stay motionless, fixed to their respective jaws.)
I don't know — perhaps the full game is more involved than that. But despite the mouth-watering graphics, the demo hasn't really motivated me to find out.
Update: One of the developers, or at least someone purporting to be, responds in the comments.