If you didn't know the title, you might not guess that this is a Captain America movie. It has most of the Avengers in it and seems very much like a direct sequel to Ultron with a bit more focus on Captain America. But since I really liked Ultron, and feel the Captain America movies are the best of the Marvel series, I'm okay with whatever they want to title this.

The movie begins with a big superhero vs. supervillain fight that results in civilian carnage. This isn't unusual in the superhero movie world, but what is unusual is that rather than glossing over this, this movie shows both the distress of the superheroes involved and the trauma of those who lost people in that fight. And that trauma leads to a request that the Avengers register with the United Nations and act under their authority. Some of the Avengers agree to this, like Iron Man, while others, like Captain America, prefer to remain free agents.

What's interesting is that rather than doing something simple, like having this be a plot by bad guys or by putting the superheroes into a bureaucratic nightmare, the movie raises the idea but throws in a big attack before the new agreement can really be implemented. And while for much of the movie it looks like the writers are more on the side of the Libertarian faction, by the end the audience is left to decide for themselves which side is right (I suspect the division line will be a political one involving how you feel about the U.N. in general).

This all sounds pretty weighty, but the movie is actually tremendously fun with a lot of great action. There's a long, amazing superhero vs. superhero fight that absolutely amazing, and the movie has a good sense of humor even as it considers very serious topics.

This is not just good for a Marvel universe movie, this would be good for an X-Men movie.