This game reminds me of an great movie or work of art. Playing the game a second time has allowed me to see the subtleties and little nuances that Rapture had that I completely missed the first time. I highly recommend you guys go through the game, even on easy to check it out again and experience, IMO, the best game (story and gameplay) this generation.

I couldn't make it through a second play through, it just bored me.

i played it a second time just for the different ending, cuz the first time i went bad and I hated the ending, I didnt know I was being evil..... but the first time through I went through it slowly.

im waiting to play through it a second time.  im hoping it'll be like a good book where you dont mind rereading it aslong as there has been sufficient time between each play through. 

I played it through once on normal difficulty and got the good ending. As soon as I beat it, I started up a new game on hard and it took me 3 or 4 sessions to beat it and get the evil ending. I am definitely playing it again to finish getting all the achievements, but that third playthrough isn't going to be anytime soon. 

Definitely the best single player experience to be had at the moment on any console.

It's so intense, that quite frankly I don't know if I can replay it anytime soon.
The experience was so rich, so amazing that I'm exhausted.

The second time was more fun to me because.
1. I mastered the weapons and the combat got more fun.
2. I understand the story better.
3. i don't save up things anymore so i threw the best ammos i've got at anything