Before I say anything, I encourage anyone who is interested in this game to go read the full interview, it's kind of long, but if you're like me and into the game, you'll enjoy reading it.
This game will have a lot of interesting new features. One of the ones near the end of the article, was; while vita-chambers are back, Little Sisters can heal the Big Daddies, so you can't just go, put a few rounds into him, die, o back. And yes, you do get to fight other Big Daddies to get their little sister. You will also be warned when the Big Sisters are coming. Either by a Little Sister, or by someone chiming in through the radio.
There is so much in this interview that I can't possibly tell you all of it as well as they did without a direct copy and paste.
For starters, when you have adopted a Little Sister and put her on your shoulder, she cannot be harmed. Just like in the first game you couldn't harm a Little Sister. The real danger for her comes from when you place her near a corpse to absorb adam.
At times, you get to go out and explore the ocean, but there won't be any fighting in the ocean. You can explore, and there are some quests to do involving them, but never fighting. And you can't swim, seeing as how you're so big and heavy.
Plasmids are going to have a bit more interactivity this time around, and you will be able to dual wield a plasmid and a weapon to use them at the same time.
Rapture has kind of been dead since the end of Bioshock 1 where you took the Little Sisters out of it. Rapture gets kick started again, seeing as how the Little Sisters have returned.
The Big Daddy types from the first game (Bounce, Rosie.) Will be returning, with a couple more.
That about sums it up the best I can without giving you a reason to actually click the link and read it yourself, but I still highly encourage you to go read it.
Part one: joystiq.com/2009/04/23/joyst...
Part 2: joystiq.com/2009/04/23/joyst...