An engaging epic with enough material for two movies. Is this a once-in-a-generation event?

Rating: 8/10 (29 April 2019)

First of all let me say that I was looking forward eagerly to this movie along with millions of others, I thoroughly enjoyed myself, and there's no doubt you get your money's worth. For the broader fantasy/adventure genre that superhero films fit into, my high-water mark is set by the Lord of the Rings trilogy. On a scale where LOTR is 10/10, I give Wonder Woman a 9, and both Avengers Endgame and Infinity War an 8. In other words, it's darn good, and it has the high satisfaction level that the Russo brothers promised us we'd get. The production values are state of the art, and the payoff is to see *almost* every MCU character present and accounted for so that we can see them in action once more.
I was surprised -- if you'll forgive the circular statement here -- by just how many surprises there were for both the plot elements and the characters themselves. It's now clear why the producers and directors kept such tight wraps on this thing before its release. Broadly speaking I was expecting that this would play out in much the same style as Infinity War, like they were the first and second halves of a 5.5-hour epic. I was wrong. It's epic all right, but stylistically, Endgame is its own film. The biggest thing I didn't see coming is that lots of the first half particularly is reflective, deliberately paced, and NOT just slam-bang CGI. As far as I'm concerned that was welcome -- the cast is populated by characters we've learned to care about so give them space to breath. It's the end of an era and it's all given a proper sendoff. At the same time, there are plenty of big, dramatic entrances that led to cheers and applause for the audience I was in. Those are glorious, and the final big action scene is over-the-top huge. The flip side, though, is that there are SO many characters in play that most of them get only a bit of screen time, not much more than cameos.
One thing that was not a surprise was that most of the Endgame storyline followed the Original Six Avengers -- Thor, Iron Man, Captain America, Black Widow, Hulk, Hawkeye for one final go-round. Mostly, it's the Three Amigos that head the list. And by the end I felt like those characters have all had lots of innings by now, it's past time to move on with all the other characters we've met and who could be just as engaging. The main "other" leads here with bigger-than-cameo roles were Ant-Man, Rhodey, and Captain Marvel, all welcome.
I think the whole 22-movie arc of the MCU, and in particular Infinity War and Endgame, might qualify for being the movie event of a generation -- i.e. something so big and involving that everyone knows about it. A generation ago, it was the Lord of the Rings trilogy. A generation before that, it was 2001: A Space Odyssey and also Star Wars, two films that laid out diametrically opposite paths for the space/sci-fi genre and have both had their successors. And a generation before that? According to my parents it was Gone With The Wind, the making of which was nothing less than a national experience on a level bigger even than we're seeing now. (Just for fun, look up how movies rank in the all-time box office list after adjustment for inflation. Avengers Endgame has a ways to go yet.)
About that 3-hour runtime. Too short for the material! Add another half-hour, put in an intermission, and then we'd have a true epic movie. Way back when, that's what big-budget epics were like -- things like Ben-Hur, Spartacus, How The West Was Won, El Cid, Cleopatra. They were great! Not just movies, but whole experiences. The intermission gave the audience a chance to do a washroom break, maybe get some more popcorn, clear their heads, then settle back in again. Endgame is *almost* there.
Some other thoughts:

Yes the big battlefield scene(s) toward the end make up a great orgy for the fans, but so much of it makes no sense. Various of the most powerful Avengers go one-on-one against Thanos and then get interrupted. Where's Iron Man when Carol is fighting him? Where's Wanda when Thor is going at him? They're supposed to be working together. This was too obviously just a way of giving everyone their chance at a big scene. This feels like lazy storytelling.

Yes! Captain Marvel is right in there and boy is she powerful, but her presence felt just a bit tacked-on -- more like a guest star. I know this was supposed to be all about the "core" Avengers, and it is, but I wish they'd worked harder to bring her right in to the center of the story. (Great CGI too that no other MCU character has.)

But this movie underscores yet again that the MCU still has a gender problem. Nebula is underused (again). Wanda is underused (again). Mantis is underused (again). Carol is uber-powerful but underused. Black Widow has been treated horribly inconsistently all the way along in the MCU films, and the way she's portrayed here is yet another example. She deserved better.

I didn't much like the way Thor was used here either. They've pushed him so far into comedy mode that he's become a clown. Bad choice! Chris Hemsworth does light comedy well, but he's equally good as the serious God of Thunder and I wanted more of that side. The first Thor movie is one of the half-dozen best superhero films ever made, Ragnarok was also great, but here the character has become almost unrecognizable. What a letdown.

And speaking of Asgard, a shout-out to Rene Russo, who's marvellous. She absolutely kills the scene(s) that she is in. We sure could have used more of her.

There's a totally fun bit on the big battlefield where all the *female* superheros gather to form a united front. More please! This had better not be just tokenism. For example, Wanda (Scarlet Witch) is shown once again to be one of the very few heroes who was able to genuinely hurt Thanos. GIVE THIS WOMAN A MOVIE!! It doesn't hurt that Elizabeth Olsen is a first-rate actor.

There's so much material that it's just an embarrassment of riches. By trying not to leave anyone out in this Grand Finale, the Russos have shortchanged various scenes that could have been better. And there are loads of deserving characters, like Valkyrie, Black Panther, Shuri, Wasp, Dr. Strange, Wong ... Too much in the last hour felt rushed.

And about time travel. I'm not particularly giving anything away to say that it's there just like everyone expected. But just like all other time travel plots, (a) it's fun but (b) this version of it doesn't make any more sense than any other movies built on the device. Bizarre logic, plot holes, missing pieces; it seems fine as it's happening, but you're left scratching your head after the credits roll.