From what I've heard it's a bit in the same vein as Fahrenheit, in the sense that very much of the gameplay is based on the player making certain choices - thus effecting the story.
I really loved Fahrenheit, and it was one of the greatest games I had played when I completed it, mostly for the power the player had to affect the outcome of the story.
Sadly, the day I bought a Xbox 360 about a year ago, I wiped out any chances of me ever getting to play this game, so pretty much what Sigz said. :/