I didn't enjoy this film, unfortunately (spoilers)
I enjoyed the dark opening scenes with the Avengers hunting Thanos, the nearly post-apocalyptic Earth, and a few key scenes during the final battle (Captain American wielding Thor's hammer and the appearance of Black Panther raised the hair on my arms). "Professor Hulk" was amusing. I also liked the nods to "Agent Carter" (Marvel's best TV series) and Steve's eventual fate.
Unfortunately, I really disliked the big middle section of the film. I found that the plot was weak (the film hinges on a rat freeing Ant-Man from the Quantum Realm), the time travel adventures verged too far on the side of overlong fan service (moments like Cap versus Cap could have been removed entirely), the humour was flippant and there was some characterization I thought was simply ... broken.
We get a lot of Nebula. Chris Hemsworth didn't have the acting chops to pull off Thor as a tragic AND comedic figure. Black Widow's sacrifice felt meaningless because a massive part of her character arc (her past as an assassin) occurred off-screen. All of Rhodey's dialogue was strangely mean-spirited.
Worst of all, the relentless, philosophical Thanos, who was the highlight of "Infinity Wars" (for me), reverted to a typical Marvel end-of-level boss in this film, replete with some disappointingly cliched "I'm gonna enjoy this" dialogue and (for some reason) a big anime-style sword.
There were also some really unearned nods to diversity sprinkled throughout the film, like the gay man in Steve's "survivor's group" and the second-tier (largely) female superheroes grouping together in the final battle. A miniscule bit of dialogue really isn't enough to say this film features "Marvel's first gay character" and grouping the female characters awkwardly together doesn't change the fact that only "Captain Marvel" has received her own solo film.
I think this film could have been great, but, ultimately, the filmmakers took the safe way out and made a three-hour film designed to placate fans without attempting to challenge their imaginations.
--------------------------------------------
You can read all of my latest film reviews here: https://www.maketheswitch.com.au/about/