I beat the game last night after marathoning all day to get through the story.  Let me say, it was an awesome adventure and the story was perfect...almost.  The ending and the final boss encounter felt extremely forced and unecessary.  They could have made the ending so much better.  The only thing that made the final fight memorable was the dialogue.  Other then that, it was atrocious. 
 
Does anyone else agree? 
 
(please avoid spoiling the story for everyone else)

How long did it take you to finish it? I think the game looks cool but dont want to buy it if its short as hell.

" How long did it take you to finish it? I think the game looks cool but dont want to buy it if its short as hell. "

Took me 14 hours to complete the game on Normal, with 100% of the Secrets, Riddles and Arkham Secrets. Without a guide. But I played around a lot.

Yeah, I would say if you just went whole hog into doing nothing but the story it's about 10 hours. You could easily finish the game in two sitting and will probably want to. The gameplay and story are just that good.
 
I will agree that the final sequence was a little disappointing. I totally didn't think that Joker would behave in such a manner. I can forgive it though as it wasn't completely atrocious. Just a little odd.

I probably spent about 17 hours on the main story just exploring and getting all the secrets and just taking in the atmosphere. But the game is far from over after the credits roll. The challenge rooms bring the same kind of addiction that Shadow Complex has for me. I just can't stop playing them. I have been doing the challenges for about 6 hours today and I don't think I will be stopping anytime soon. I have to shave more milliseconds!
  
P.S. Had to take out my edit it had spoilers.
 
P.S.S. My edit said I enjoyed the ending. I am not sure why everyone is poo-pooing on it. It really couldn't have gone any other way without it being totally a one-sided fight.

The only problem I really had with the game was the Killer Croc level. It was boring and repetitive, but the game was great overall.

" I probably spent about 17 hours on the main story just exploring and getting all the secrets and just taking in the atmosphere. But the game is far from over after the credits roll. The challenge rooms bring the same kind of addiction that Shadow Complex has for me. I just can't stop playing them. I have been doing the challenges for about 6 hours today and I don't think I will be stopping anytime soon. I have to shave more milliseconds!    P.S. Had to take out my edit it had spoilers.  P.S.S. My edit said I enjoyed the ending. I am not sure why everyone is poo-pooing on it. It really couldn't have gone any other way without it being totally a one-sided fight. "

The game took me about 11 hours and I didn't even get all the riddles and secrets yet.
 
This game is just worth buying, because it's a freakin awesome game.

Agreed, the ending boss was a let down. But it didn't ruin the adventure to it.

" The only problem I really had with the game was the Killer Croc level. It was boring and repetitive, but the game was great overall. "

The only thing I can say for the last 2 boss fights is that they were out of character and that the developers probably ran out of ideas by that time. The Ivy fight could've been done a bit differently since I just don't think a fist fight with a giant plant is something even batman would do. If you can recall, none of the previous boss fights were ever about straight-up brawls (Harley is probably an exception but technically, you never fought her directly). Even the fight with Bane was about taking advantage of his weakness instead of beating him to submission. Personally, I would imagine the Ivy fight to be something similar to Scarecrow's in that you traverse the environment and take advantage of any surrounding object that can harm the enemy.
 
As for the Joker fight......well what can I say? I personally don't think there was any need for a final fight with the Joker at all. Batman's fights with the Joker were always about foiling his plans and just knocking him out with a punch at the end of it all. I can sympathize with the developers though. They had to put a game in there one way or another. Designing a Joker boss fight is like making an FPS game for the movie Citizen Kane. It just doesn't work unless you're into the Adam West stuff.

yeah the joker fight was a bit disappointing and easy

The game is flawless story wise until literally the last 15 minutes where it seemed like there could have been a lot more game left but they all of sudden go oh yeah go do the final boss. That entire sequence aside from being terribly forced also felt completely contradictory to the entire Batman mythos. Even though it was written by Paul Dini it felt like borderline fan-fiction.

i thought the dialogue saved the final boss fight.  In a video game you have to have a boss fight or something like that at the end.  yes i was over the top but i think the story telling at the end was ok.