How long does it take to beat this game???

If you rush through it, you can probably finish in about 10-12 hours. A conservative estimate would be about 15 hours if you play normally. The game requires two playthroughs to get all the achievements and to see both endings, so the length doubles right there.

Whether you rent or buy, you should not miss this game!

yup, what vpn75 said. The game rocks.

360 version looks to be 49$ at bestbuy this week. Great game.

The game requires two playthroughs to get all the achievements and to see both endings, so the length doubles right there.

Why does it require two playthroughs? (I have not played it yet.) In some reviews I read that you can choose to either murder or spare the Little Sisters. Is that where the different endings comes from? Or is it for some other reason?

Why does it require two playthroughs? (I have not played it yet.) In some reviews I read that you can choose to either murder or spare the Little Sisters. Is that where the different endings comes from? Or is it for some other reason?
Yes there is more than one different ending which requires you to play it a second time either saving or harvesting all of the little sisters. Awesome game. Highly recommend it.

I don't have an exact time it took for me to beat it but it felt like a long time (compared to Halo 3). It's not so short that you feel short changed but it's not so long that it feels like the game is just dragging on. Regardless, it's an excellent game.

And you don't really need to play through the game twice to see the endings. If you only like playing games once then check out Youtube to see the other ending you missed.

Took me around 12 hours to beat this on Hard (and I didn't rush through it at all). For comparison, Halo 3 took me about 10 hours on Heroic. Halo 3 was much harder, though. So I'd say Bioshock is quite a bit longer.

I'm also not sure it requires two times through to get both endings. I don't know how many Little Sisters must be harvested to get the other ending, but I don't think it's all of them. Probably just more harvested than saved. It's also really not worth playing through a second time solely to harvest Little Sisters. There is very little impact on gameplay. If you really enjoyed the game, like me, then it's definitely worth playing multiple times anyway, so it's cool that there are options for how to play it.

I spent about 3 to 5 hours on each level, but I was taking my time, looking and finding everything to get all the achievements.

If you play it....play it on Hard, and look through absolutely everything. It will take around 20 hours if you really comb through everything in the game. You can get all 1000 achievement points doing it this way as well, if you wait before you waste Cohen.