Well what do you know? We have another Bioshock E3 preview, this time from IGN

The demo started out with your character in the middle of a marble hall, surrounded by glass windows and wooden planks for reinforcement. Cracks, debris, and other signs of wear were all over, proof that Rapture's residents no longer cared for cleanliness. Their concerns were decidedly elsewhere, irrefutably proven when we met the first shambling character. From behind a walk stalked a Big Daddy, a hulking humanoid covered in thick, cumbersome underwater equipment. Instead of charging right at us in a murderous rage, he slowly stepped by, aware of but uninterested in our presence. This gave us a sense of Rapture's autonomous natures. We're not the person around all the action revolves; every enemy is just trying to live its own life.