Joss Whedon promised us a "darker" sequel; did he succeed? It would appear yes, but that isn't necessarily a good thing.

What made Age of Ultron a "must see" for most is the simple fact that it comprises of characters we've had to watch in separate films. It was just the thrill of seeing Iron Man and Thor, two stars of their own individual films, meet up once again! This was the selling point for the first Avengers, and clearly it has succeeded again. However this may have been "milked" as there were clearly some characters that were there just for the sake of it, without any real need or purpose to serve the plot. This could have been time better spent explaining the events that took place between Age of Ultron and the previous Marvel films. The performance of Paul Bettany and James Spader as their Vision and Ultron were absolutely amazing, but not enough to justify the excessive final battle scenes.

After the first Avengers, the individual character story lines about the Hulk, Black Widow and Hawkeye seemed to compensate for the lack of character depth (seeing as the other Avengers all have their own movies). However, this I felt was again excessive. As a sequel, Age of Ultron avoids the (necessary) burden of having to spend the first half of a movie developing its characters. Without revealing too much, it seems that the movie jumps straight into the plot "for the sake of it", just because it can.

In summary : Good cameos, great additions to the cast, but poor development, cliché sideline stories and fight scenes that seem to have lost their charm. Not to mention unanswered questions between the two Avengers movies, as well as the other Phase 2 movies. And to make it matters worse, nothing more than a slightly anti-climatic mid-credit scene.