SPOILERS AHEAD
The story is good, characters are quite good, CGI is amazing, and there are many delightful/unexpected surprises. The visual surrealism from 2016's Dr. Strange is also in this movie, but some of it was traded for horror/frightening moments (a fair trade off which gives us something new). Eilzabeth Olsen's acting really enriches every scene she is in. Strange, Chavez, and Maximoff are all relatable and have emotional profundity. The use of magic musical notes in the fight between the two Stranges was very creative. In some ways, this movie is a breath of fresh air. My only criticism is how the story writers butchered Wanda's character (literally and figuratively). In WandaVision, we got an in-depth look at Wanda's character. We saw a person that earnestly tried to escape reality to pursue happiness, only to come to terms with grief and then rectify her wrongdoings that were unintentionally caused by seeking that happiness. This earned the audience's empathy, but that empathy is gradually thrown out the window throughout the course of Multiverse of Madness. Every time Wanda kills someone in pursuit of a happy life with Timmy and Tommy (something she had seemingly sacrificed by the end of WandaVision) the person watching the movie feels torn in two. Her redemption arc at the end of the movie felt rushed, as it could have and should have been done much better. Many people were simply unwilling to accept Wanda as the movie's main villain. Obviously, this IS NOT Elizabeth Olsen's fault. In my opinion, the clever way she played the character partially compensated for story writers' poor integration of the character. On an unrelated note, you need to have seen (at least) WandaVision, the original Dr. Strange movie, Infinity War, and Endgame to fully appreciate this movie. A general familiarity with the Marvel Cinematic Universe is not necessary to enjoy the movie; it's still a great movie without any prior context. But on average, people who have been keeping up with the MCU tend to like this film more than those who have not.