As with every sequel, things must get bigger and louder.  Unlike the first film, the danger really comes from within.  Tony is obsessed with changing the way things are done by building a peace keeping for that will put an end to the need for the Avengers.  He has been working on an A.I. to watch over the world and prevent tragedy.  Even as the Avengers are in action, he has Iron Man like robots trying to do crowd control.  But the people are not as confident.

When Tony gets access to some Asgardian technology, he recklessly uses it to try and jump a hurdle with his A.I.’s processing power.  Of course it goes wrong, resulting in a mad child called Ultron.  Ultron constantly works to better himself.  And one goal is to put an end to the Avengers.  Not quite in the way Tony anticipated…he was thinking retirement.  Ultron is thinking annihilation.  To better reach those ends, he brings brother and sister Pietro and Wanda Maximoff.  The orphans consented to Hydra experiments that have given them super-powers.  Pietro is the super-fast Quicksilver and Wanda has reality warping powers.

In a confrontation with Ultron, the Scarlet Witch manipulates several Avengers, including the Hulk who goes on a rampage.  Eventually the reveal of Ultron’s plans (including wiping out the human race) horrifies his cohorts.  His continuing evolution actually leads to the introduction of a new character for the MCU.  The Vision is introduced when the Mind Stone and lightening (along with the Jarvis AI) are combined to create the Vision.

Age of Ultron tries to be the Empire Strikes back, and is certainly loaded with darker themes than the previous films.  The performances are strong, and when the Scarlet Witch exposes Iron, Cap, Black Widow, Thor and the Hulk to their greatest fears of their past or potential futures, it threatens to break their bond apart.

The action is top notch.  There are several excellent and memorable fight sequences.  The jokes mostly land (but who thought it was a good idea for Tony to suggest if he can lift Thor’s hammer that he would reinstate the practice of kings sleeping with new brides on their wedding night).  There are a couple running jokes that can be particularly entertain.  The running gag about lifting Thor’s Hammer (which has a very good payoff) is especially fun.

The movie gives more attention to Hawkeye.  There was talk that Renner was very frustrated with the path the character took in the first Avengers.  This may be Whedon’s way of saying “sorry” to Renner.  It also establishes firmly the friendship with Natasha.

The effects are very good.  Vision looks very close to his comic book counterpart, without looking to fake.  Yet he is slightly unnatural.  Which is kind of the point.  Bettany gives life to the role.  It only took his seven years to be more than a voice-over (now he is a motion capture voice-over).

The film faced some criticism over Natasha calling herself a monster to Bruce Banner.  Some viewers felt the takeaway was that Natasha saw herself as a monster due to being sterilized.  I don’t know that I accept it was that clear cut.  Because the film is quite direct that it is the idea that she was a cold and efficient killer, and the folks who sterilized her believed this would make her that cold and efficient killer.  But I will agree it was somewhat clumsy in the writing, and Whedon deserves the credit for that.

In the end, I enjoyed this second outing with the Avengers.  It has some weak points, but nothing that ruined the overall enjoyment.