I watched the movie at a midnight showing my friend invited me to last week. I like it very much, overall. It certainly feels like a victory lap for the entire series and has plenty of incredible moments. But I also wish they hadn't gone the time travel route and thought that certain character arcs weren't handled very well.
Time travel is the ultimate can of worms and I'm growing increasingly frustrated with various screenwriters using it as a magic plot bullet whenever they've written themselves into a corner. It always requires a lot of exposition and almost never holds up under scrutiny in my experience. The closed loop model shown in 12 Monkeys runs into the issue of Determinism headfirst and almost always turns the characters into glorified marionettes. The endlessly branching timeline model used in this movie poses an equally endless number of "But what if?" questions. The otherwise very entertaining
NYT interview with the writers just skirts around the issue and doesn't provide any satisfactory explanation. A quick joke and a hand wave, just like in the movie.
It's all fun at first, with characters meeting their past selves and having existential conversations and whatnot, but it always sends my brain into the most frustrating feedback loop as to how the logistics of everything play out. Other plot devices don't have the same issue. The Arc Reactor being a nearly limitless source of power is relatively straightforward. Same with the Super Soldier serum turning Steve into the personification of human physical potential. None of those are real, but plausible enough that once you buy into them, everything more or less falls into place. Even the Infinity Stones themselves are more or less straightforward.
So with all that said, I don't really understand how the Old Cap end scene is supposed to work exactly and it left me with more questions than answers.
The Ancient One pretty much says that going back in time creates a branching alternative timeline from that point on. That also means that a character from 2019 traveling to 194X can not just wait a few decades until he is back in "his" 2019 again. So he must have quantum'd back somehow. How/When/Where?
In his new 194X life with Peggy, does it mean that there are two Caps, one in the ice and one at home?
The movie sorta implies that Steve kept a low profile in his new life so as to arrive at his foregone conclusion, which would be completely out of character and adopt the closed timeloop model the movie otherwise dismisses.
I've read interpretations that Steve was Peggy's secret husband all along, even in the main timeline. This is almost impossible to reconcile with the scene in WS in which Peggy reminisces about her other(?) husband while having an Alzheimer's episode right in front of Steve. She wouldn't have been in any shape to keep up with such blatant lie by omission when talking in private to her closest confidant.
If Steve's motivation was to go back to the world he grew up in and felt more at home in, why didn't he take Bucky with him, who is equally displaced and wanted as a fugitive with a tarnished legacy in 2019? They could have easily written that in. "Wait up, Steve. I'm coming with you just in case.", with the two of them implying that they've talked about it in private beforehand. It's completely out of character for Steve to leave Bucky behind to play second fiddle for a potential new Cap after everything he was willing to do and risk for his childhood friend just a few movies ago.
Speaking of Bucky, he never got any face-to-face resolution with Tony, which rubs me the wrong way. The entire movie just brushes him to the side, which is especially surprising to me since the Russos had done such a great job with him and Steve in WS & CW.
Maybe there is a perfectly acceptable explanation to all this and I'm just too thick to grasp it. But the more I think about it, the more it sounds to me like the writers just wanted a bittersweet ending for Steve and shoehorned in a scene in which he passes on the shield to Sam and handwaved the details because "quantum". Tony's conclusion feels earned and sensible. Steve's does not.
Further observations:
Acting was very good overall, as usual.
I like pretty much everything with Black Widow and Hawkeye.
I like Tony's entire arc, from start to finish.
The final action set piece might be one of my favorite action scenes ever. Loads of dope moments, from the frame-perfect initial standoff between Cap and Thanos' army, Steve wielding Mjolnir, the dusted coming back, "Avengers! ...Assemble", Pepper in the Resue Armor, Scarlet Witch throwing down, "I. Am. Inevitable.", the IronSnap. Dope.
Hulk was a bit shortchanged, I think. Professor Hulk is a neat concept, but the character progression happened pretty much off-screen and he never really got any solid action moment. For the final story of a team he's supposed to be a cornerstone of, I expected more.
Fat Thor is funny enough, but I wasn't a fan of him joining the Guardians as a comic relief and leaving his people in the hands of a reformed slave trader at the end. I thought his previous arc growing from a reckless meathead into a responsible leader over the course of several movies was very enjoyable and even fairly convincing, all things considered. This is completely out of left field in comparison.
Since 5 years have passed in-between the ThanosSnap and the HulkSnap, I hope that a minimum of real world ramifications will be shown in Spider-Man FFH.
Some people have speculated that the global wave of energy present in this movie might be used to introduce the X-Men to this universe later down the line. Pretty slick if so.
PS: Basically, most of my complaints are the result of dozens of unaffiliated writers working on the same universe for over a decade and their visions not being sufficiently compatible with one another. I can't imagine how daunting it must be for Feige to put all these puzzle pieces together year after year, but there is one too many incoherence in this one for my liking.