I just finished it myself. It was less than 4 hours. I tend to take my time by clicking through and trying everything. When I'm pretty confident I've figured out a solution, I save it for last.
It was a very smooth play through and I never got stuck. Tim spoke about his concerns that people might be frustrated with getting out of Shay's "routine", but I never got hung up on it. I guess I was a little spoiled from the documentary and I made the connection at the beginning that I was going to have a never ending cycle to get out of. Minor spoiler warning: I felt like the original trailer kind of hinted the solution for me too (at least from my memory of it). I went through each of Shay's "missions" once only to see everything.
Perhaps there was too much play testing to help steer inexperienced adventure gamers? Maybe Broken Age could benefit from two difficulty settings like in The Curse of Monkey Island. That way experienced players could still enjoy a challenge.
I would have preferred more difficulty and more length, but it was an amazing game from start to end. Obviously, the story was extremely well done. After Vella met the DEG (I'm using a deliberately vague abbreviation), I thought I had it figured out but the ending was unexpected for me. Instantly, everything came together and I literally said out loud, "Holy sh**."
By the way, I really, really appreciate the fact that the ending treats the audience like adults and allows us to make the connections ourselves! I'm so tired of Hollywood spoon-feeding the storyline. I hate when the climax arrives and the gratification of putting the pieces together is stolen with some condescending flashback. It's as if to say, "Hey guys, remember that one scene from earlier in the movie? Does the ending make sense now? How about we show this part too? Still can't get it? How about we have a character narrate the plot points for you?" Good example: Life of Pi.
Also, I was actually surprised at how polished the game was. This looked and played much better than many other commercial games. The only bugs I experienced were rare graphical glitches (usually z-axis/overlay swapping).
Pros: Incredible story, characters, and ending. It had just the right amount of comedy for this setting. Superb adventure. Fun and logical puzzles. Beautiful art; every single frame of every single scene was like a hand crafted piece of original art. Loved the animation; everything seemed so alive because there was so much detailed movement! Excellent voices, music, and sound.
Cons: Wasn't challenging enough for my taste. I was hoping it would be a bit longer for the "first half".
Overall: Amazing experience. I loved every minute. Maybe I'm bias but I honestly think it deserves around a 9.5+ out of 10.
Thanks Double Fine!