IGN just posted a very interesting video: Bioshock 2 9 Minutes Walkt-Through

In a nutshell: you play as a big daddy; can have your own little sister which will harvest for you; big sister will harvest you

Other Points-of-interest: you can explore the ocean outside the Rapture. While little sister is harvesting for you, you have to defend waves of splicers- survival mini-game.

http://uk.xbox360.ign.com/dor/object...lk051209c.html