Bioshock 2 Impressions

I rented Bioshock 2 from the old neighborhood Blockbuster and have put a few hours in (just took down some reverand fellow), so I feel like I'm far enough in to give some decent impressions.

I like playing as a Big Daddy and love the act of harvesting Adam.  I've saved every single Little Sister so far (and will save them all).  To me, the act of harvesting is as much fun or more fun than the actual single player storyline.  I feel that the storyline is very weak thus far, but then again, I'm not all the way through it yet.  In the first game there was a definite twist in the story that I loved and the first Bioshock had one of the best stories in any game I've ever played.  I'm disappointed so far because it just seems so much less interesting than the first one.  The levels in the first game added so much to the storyline, but I feel that the levels in this one are just window dressing.  I have a bit of Godfather III feeling with this game thus far.  It's great, but it's not the first Bioshock.  As of yet, I just really don't care that much about subject Delta.  It would have been nice to have had a bit more backstory.  Also, the antagonist in this game just isn't as compelling as Andrew Ryan and Frank Fontaine from the first game.  It's nice that there are a few throwbacks to the first story, but I can't help but think that the story of Rapture should have ended with the first game.  I'm hoping 2K wins me back in the latter half of the game, but at this point, I'm just not sure.  I don't mean to bag on the game because it is very good, but when the first game had such a grand storyline and new ideas, anything that comes afterwards will be a huge disappointment.  I'll be sure a post a mini-review when I finish.