When a Bioshock Infinite video arrives in my lap, which is how I demand delivery of all gaming news, I do not expect it to feature actual human beings speaking at me. Ziplines and plummeting are gravely missing from this video. Although it does contain game footage, it's mainly Ken Levine talking about the world he's creating, which he sees as but one of the game's main characters.
There's a focus on actual people characters, with the voice actors behind Booker and Elizabeth also featured, breaking the rule that they, being the opposite of Victorian infants, should be heard and not seen. Now, in my mind's eye, Booker Dewitt will always look like Troy Baker, whose name should immediately be attached to Syndicate's antagonist.
There's a sense of flexibility and collaboration in the design process, which could be part of the reason this is Bioshock Infinite rather than Ken Levine's Columbia. I don't know how well Ken Levine's Rapture would have gone down as a title though. It sounds like an astonishing game, just not necessarily one I'd be keen to play.