So I went to see it and I'm still in shock. The non-spoilery review basically goes:
This was 2 hours and 45 minutes of non-stop action. Mostly battles, with small scenes in between of people trying to get to other battles. A few good jokes, laughs and one-liners, one of the best interactions being a mutual Flashdance appreciation moment between the two Peters (Quill and Parker).
Go in with an empty bladder and DO NOT buy that mega-cup of soda. You don't want to miss a second.
Now we are going to get to the spoilers. I'll start off mild and work my way up, OK? I'm going to make lists and categorise them.
Not sighted in the movie, absence unexplained:
Valkyrie. Idk where the hell she was. Literally no idea.
Nakia. Ditto, but at least she didn't inexplicably vanish off a spaceship between one movie and the next.
Mentioned but not sighted:
Clint Barton
Scott Lang
Natasha mentions that they 'took deals because of their families' and are 'under house arrest'.
Seen during the movie but undetermined at the end, presumed OK:
Pepper
Wong
Shuri
Still with me? OK. Now we get the BIG spoilers.
The basic premise, as you probably know, is that Thanos wants all the gems in the Infinity Gauntlet to wipe out half of all life because... well, he's basically an ecoterrorist fighting overpopulation.
The movie is one long series of running battles trying to stop him collecting the gems. During those battles, the following characters get killed. I'm presuming permanently. Thor certainly thinks so, and he witnesses several of the deaths.
I'm listing the deaths in order, as best I remember. Note, the first two are in the first 5 minutes of the movie. You will be SHOOK.
Dead in battle
Heimdall
Loki
The Collector
Gamora
Vision
At the end of the movie Thanos has the completed gauntlet. He activates it. Half of the population of the universe vanishes, turning to ash in what I am henceforth calling The Dissolving. The following list of characters get dissolved... I think this is roughly the order in which they go.
Dissolved by Thanos
Bucky
Wanda
Sam Wilson
T'Challa
Groot
Mantis
Drax
Peter Quill
Stephen Strange
Peter Parker
Maria Hill
Nick Fury
The last two go in the very-end-credits scene (there isn't a mid-credits scene) in which Fury activates a pager which sends a message before he dissolves. Captain Marvel's logo appears on the screen.
Still standing at the end of the movie
Tony Stark
Nebula
Tony is injured and he and Nebula are stuck together on Titan. Which. Yeah. That'll be a fun trip home. Everyone else on the below list is at the final battle site in Wakanda but definitely still standing.
Steve Rogers
Natasha Romanoff
Thor
Bruce Banner
Rhodey
Okoye
M'Baku
Rocket
... that's it. Oh, and Thanos. Pretty much every other bad guy seems to be down, but Thanos is still standing and he still has the Gauntlet, though it appears damaged.
One more shock which I REALLY didn't see coming:
Red Skull is in it, on an alien planet, as the... gatekeeper, I guess? to the Soul Stone.