Full disclosure: the press screening for Thor: Ragnarok ended in a modest kind of film-reviewing disaster: the audio for the movie cut out about five minutes before the end of the film due to an automation problem with the digital print. And then the theater staff couldn't go back and show us the conclusion of the film again because the film studios have locked down their digital prints with copyright-control software. Before digital projection, this wouldn't have happened. Before movie theater automation, this wouldn't have happened. But even if it had happened before digital projection, the projectionist would have just been able to show us the final reel of the film. So through a comedy of errors inspired by automation and overly obsessive protection of copyright, I didn't technically watch the end of Thor: Ragnarok. In any case, this review is going to be spoiler-free as possible.
Thor: Ragnarok is clearly the best Thor movie Marvel Comics has made. That's not an achievement; the other two Thor movies were pretty bad, and they seem to be deteriorating in watchability at a remarkable clip as the years pass. But Ragnarok is better than "just" the best Thor movie. While it's not a great movie, it definitely contains many pieces of great movies in it.
The first thing Ragnarok does right: it basically throws out the character of Thor as we know him in the Marvel movies. By taking advantage of star Chris Hemsworth's remarkable comedic skills for the first time, director Taika Waititi's Thor is much funnier and more colliquial than we've ever seen. (Much of the dialogue in the film is clearly improvised; a random IMDB trivia bit randomly entered by some random person puts the amount of improvised dialogue at 80 percent, and that feels right to me.) The movie is a comedy first, and an adventure film second.
The second thing Ragnarok does right: it lets the cast run wild. Tessa Thompson, as a rogue Asgardian warrior, is a welcome addition to the Marvel films. Jeff Goldblum is wildly funny as an alien overlord. Cate Blanchett doesn't have much to do as primary villain Hela, but she vamps and camps with exactly the right droll sensibility. Idris Elba and Karl Urban and Anthony Hopkins also don't have much to do, but they don't feel as perfunctory as great supporting actors have in past Thor films, either. Waititi voices a giant rock man from space who is one of the best comic relief characters the Marvel movies have yet produced.
The third thing Ragnarok does right: it doesn't spend much time building on the Thor mythology that we've seen in past films. Instead, it finds the elements that work in the best Thor comics and smashes them together into something new. The design is straight out of Jack Kirby's sketchbook, making this maybe the best-looking Marvel movie as a result. Like the best Thor comics, the film spends a lot of time in outer space being as weird as possible. And every visual that's not ripped from Jack Kirby is instead cribbed from Walt Simonson's visually distinctive run on the character. Fans of the Simonson books might not enjoy the flippant way the film deals with his comics at times, but that's a silly argument to make; his books are still out there for fans to enjoy, and the movie will likely push more readers to Simonson's work.
But beyond the comedy and the visual flair and the fine performances and the excellent score from Mark Mothersbaugh (this is one of the only Marvel soundtracks worth noting,) you've got a fairly standard comic book movie. The villain has an army of disposable CGI soldiers. There's an entirely pointless superhero cameo. And I'm unsure how much of it makes sense to anyone who hasn't seen every previous Marvel movie.
But holy shit: a terrific sense of humor and a beautiful comic-book-y aesthetic and a vibrant spirit of behind-the-scenes fun can go a really long way. This is the most fun I've had at a Marvel movie since — oh, the first Guardians of the Galaxy movie.