Overall, the movie was well-written and acted. This isn't surprising, given the sheer number of veteran actors involved. Chadwick Boseman, who plays the title character, has played starring roles in three different movies since 2013, and he is joined by the likes of Michael B. Jordan (best known for playing the title role in Creed), Alfre Woodard, Forest Whitaker, Andy Serkis (whom I didn't recognize with a beard and without CGI), and Martin Freeman.
The script by director Ryan Coogler and Joe Robert Cole is deeper than the average Marvel movie script, raising the kind of issues that have only been addressed by the Captain America movies The Winter Soldier and Civil War (the latter of which introduced Black Panther to the MCU). Questions like "What is the responsibility of an advanced nation to the rest of the world?" and "What is the nature of authentic patriotism?" Coogler and Cole are also willing to raise the stakes through the roof at the end of the second act and beginning of the third. The characterizations are marked by nuance. There is not a single perfect character in the movie, at least among the characters who get enough screen time to be looked at in depth. Even the villain has an understandable motive and a sympathetic backstory.
Overall, Black Panther is an enjoyable and thoughtful action movie that will probably be enjoyed by anyone whose politics aren't too right-wing, for reasons detailed in the spoiler-filled section below.
And now, without further ado.....
Coogler and Cole are constrained by the conventions of an action movie, but they manage to include little moments that show who the characters really are. This is best shown in their treatment of Erik Killmonger. This is a character who can give a museum director informed lectures on the history of colonialism just prior to a heist, in a scene that shows both his education and his motives. However, this early establishment of a sympathetic goal is tempered by other aspects of his personality that are shown later. First, in a climactic confrontation with his partner Ulysses Klaue, he shoots his girlfriend without a second thought to kill Klaue and secure Klaue's plane for travel to Wakanda. This demonstrates that he is a sociopath who only values other people to the extent that they're useful to him. Then we find out this trait applies on a larger scale, too. After drinking the heart-shaped herb and visiting the ancestral plane, he orders the priests to burn the rest of the herb. This demonstrates that he doesn't value Wakandan culture or traditions, but sees his ancestral homeland as just a means to an end. Of course, it probably didn't help that his vision showed him how much of an outsider he is, with vertical blind slats in an LA apartment separating him from the supernatural African savanna that T'Challa experiences during his visits to the ancestors. These incidents show that Killmonger was a danger to himself, Wakanda, and the planet even though he shows signs of genuine humanity in defeat. It seems that he only comes to love Wakanda moments before his death, and that may be the most tragic thing about this film.
The script follows a lot of the conventions of screenwriting. The three-act structure is clearly visible, and everything that is invoked in the second or third act is introduced early on. Coogler and Cole could be accused of creating a boring, paint-by-numbers Chekhov's Armory if many of the later references didn't have a twist (like the differences between T'Challa's and Killmonger's visions in the ancestral plane, having a different virtual pilot the second time that technology is used). The writers' willingness to play with expectations is another of the script's strengths.
My only real quibble with the script is the sudden appearance of the mountain tribe in the final battle. I know we all love the original Star Wars (Episode IV: A New Hope my ass), but in that film, Han Solo had developed relationships with Luke and Leia throughout the movie. In this case, there's no plausible reason for the mountain chieftain to change his mind, kid. Nor is there any indication that this character is meant to experience character growth in this story. I don't know, maybe there will be a Black Panther 2 that will prove me wrong. But that's one minor flaw in an otherwise very good script.
Much has been written about the political implications of this movie. Most of this has been about the idea of Wakanda as alternate vision of an African nation with lots of technology that was never colonized, but I think this movie addresses political issues in other ways.
First of all, there is the debate the characters constantly have about what role Wakanda should play in the world, particularly regarding the African diaspora of black people throughout the world. Should it share its technology with the world -- particularly people of African descent? Or should it continue its policy of isolation and carefully hide its secrets? If you take out the advanced technology and the racial component, this debate mirrors the history of the United States in the 20th Century (and arguably the early 21st). It plays like a critique of American history disguised by setting it in another culture. The film's answer is the question is that an advanced country has a duty to the rest of the world, but that duty is not to overthrow governments and impose its own idea of justice on the world. Rather, such a country should improve the world through cultural outreach. Honestly, given these themes, I'm shocked I haven't heard about even more conservative and racist resentment on the internet than I have. I mean, the movie ends (in the first easter egg) with a black African country declaring its intention to be an example to the rest of the world. This should be enough to give proponents of American exceptionalism and white supremacists a stroke.
I suspect the reason we haven't seen maximum apoplexy among conservatives who aren't blatantly racist is the way the film couches its anti-imperialism. The only country that is ever explicitly identified with the imperialism both T'Challa and Killmonger despise is the United Kingdom, not the United States. I assume this gives some people a fig leaf they can use to ignore the United States' role in perpetuating the legacy of imperialism in the late 20th Century. However, Killmonger grew up in and was shaped by inner-city Los Angeles, and that experience clearly shaped his ideas about the predicament of black people around the world. Also, it was his time in the United States that radicalized Killmonger's father. It doesn't take a lot of deep thought to realize that America is implicitly part of the problem the characters see in the world. It's amazing to see such a position even being hinted at in a mainstream blockbuster action movie.