I liked The Avengers, though not as much as many others. I felt that it (perhaps unavoidably) ignored the character development that had defined the other Marvel Studios movies and the best superhero films in favor of action. The main arc in terms of the characters’ relationships to each other was the team’s struggle to overcome their bickering and work together as a team to defeat a powerful enemy.
The good news is that there is more character development in the second Avengers movie, Age of Ultron. Among the protagonists, the relationship between Black Widow and the Hulk is explored, we learn more about Hawkeye’s background and his life outside of the team, and the complex personal failings of Tony Stark/Iron Man play a central role in the plot.
There are also a few new wrinkles, though they are arguably underexplored. First is the question of whether artificial intelligence should be created, and what kind of care should be taken in that endeavor. You can argue that the creation of the titular villain Ultron replays the issues with the creation of Frankenstein’s monster in the space of a few minutes. In both cases, a new intelligence is created by someone who has underestimated the complexity of the process and their responsibilities to guide their creation (in the case of this movie, because the creator is too busy partying). The creation of another new character, the Vision, raises all sorts of potential questions about what qualifies an entity as a living being and whether living beings have the right to live, but these questions are never really explored (or even asked). After all, the movie was running long and Joss Whedon was contractually obligated to include a certain number of action sequences.
Unfortunately, Age of Ultron repeats a lot of the motifs of the first movie. The most noticeable example is repeating the sequence of an outside force manipulating the Avengers to bicker among themselves, forcing them to discover the value of working as a team. This angle was so prominently played up that it gave me a sense of deja vu. It is the single biggest weakness of the movie. What’s worse is that, with two-thirds of the team replaced at the end of this film, we can probably look forward to seeing this kind of arc repeated in the third installment, as the new members learn the value of working as a team. Captain America seems to be setting that up in the final scene....
Overall, The Avengers: Age of Ultron is an enjoyable movie, though it sometimes feels less like a sequel than like the first movie remade and done better.