Okay, review time. What I'll do is put a long plot synopsis, and folks can ask specific questions.
First, the film totally delivers on its promise, but there were no cheers at the end as it finishes on a very sombre note.
This is the MCU's equivalent of the Empire STrikes Back, it's long but never drags. I think it reaches a new height of epic, in comic book films, definitely a one up from Civil War, and it makes Age of Ultron look a bit mediocre in comparison.
It juggles characters really well, but I would say that the best character is Thanos, while the other stand-outs are Strange, Starlord and Spidey. Everyone else has very limited time/dialogue. Thor and the guardians gel really nicely - and Thor is still very much the Thor we saw at the end of Ragnarok, hopeful even in the face of total catastrophe. Cap is very quiet in this one - Tony and Strange have a great dynamic, as their enormous egos collide.
As a summative comment, I would say it's
mind-blowing, and more than an Avengers film, it's really a "whole MCU except Hawkeye and Ant-man" film.
However, Thanos is the de facto main character, and he's the best cbm villain since Ledger's Joker. He's better than Hela, because he's better developed and his motivations (while crazy and monstrous) are better explained.
Plot synopsis (just ask if you need more details)
-Film starts with Thanos aboard the Asgardian refugee ship (Thor later says that Thanos killed half his people - and killing half a population is Thanos' MO, so it seems reasonble to assume that half of the refugees escaped). However, Thanos threatens to kill Thor (frying him with the power stone) unless Loki hands over the tessaract. Hulk attacks and gets KO'd after a short fight, a mortally wounded Heimdall channels Bifrost energy to send Hulk back to earth, before Thanos finishes him off.
Thanos then takes the tessaract/space stone, kills Loki and then uses the power stone to blow up the ship.
- On earth Banner crash-lands in the sanctum of Dr Strange, who summons Tony Stark and they discuss the coming threat. The Black Order arrive, via spaceship and fight with Tony, Strange, and Spidey - Banner cannot change to Hulk
Strange is taken (sorry I don't know all the Black order's names) because the time stone cannot be removed from him. I think by Ebony Maw, but Tony and Spidey stow away abord the ship and are able to breach the hull sending Ebony out into space, while freeing Strange.
There's some great dialogue between Tony and Strange, Cumberbatch and RDJ really play off each other nicely.
Meanwhile the Guardians of the Galaxy respond to the Asgardians' distress signal and come across Thor floating in space. They bring him aboard and there's some typical guardians hilarity as Quill is clearly intimidated by Thor.
I found this bit really funny, and nicely in keeping with the general guardians' tone of silliness - and post-Ragnarok Thor totally fits in.
Scarlet Witch and Vision are attacked in Scotland, by a couple of Black Order thugs. If Big Thor and Surfer are reading this, Scarlet Witch needs to go up a power tier, based on her feats in this movie.
Anyway, Falcon, Widow and Cap show up and save the day.
Gamora's childhood abduction is shown in flashbacks - it's quite emotional. The relationship between Thanos and Gamora is well done, and convincing - which sets up what happens later on. She makes Peter promise to kill her if she's taken by Thanos, as only she knows the location of the soul stone.
Thor , Rocket and Groot head to a galactic super-forge to make a weapon to kill Thanos (the same place Mjolnir was forged) while the others head to Nowhere. Rocket gives Thor a prosthetic eye.
There's a reunion between Banner, War Machine, Cap, Widow, Vision, Wanda and Falcon, and they give a hologram of Secretary Ross some attitude. They decide to head for Wakanda.
(hey if I leave any bits out, let me know).
Meanwhile Strange, Spidey and Tony crash land on titan (Thanos' homeworld).
The other guardians (Star Lord, Gamora, Drax and Mantis) arrive on nowhere where Thanos is torturing the Collector for the reality stone - but its all an illusion to draw out Gamora, and the whole place has already been destroyed by Thanos, who teleports away with Gamora.
Thanos and Gamora have a chat, and he reveals that he's captured Nebula, and is literally pulling her to pieces, which forces Gamora to reveal the soul stone's location.
In Wakanda, T'Challa and the general give Bucky a new bionic arm.
Gamora and Thanos arrive on a planet whose name escapes me - but its an empty dark ruin. They meet a ghostly Red Skull, who guides them - and he's way better than the Red Skull in TFA. He reveals that to obtain the soul stone Thanos must sacrifice something he loves.
This is the best Thanos moment - because Gamora laughs at him, mocking him because he loves nothing, but he turns to her and reveals that he's been crying, because he actually loves her. This is such an important scene, because it properly establishes Thanos' motivation, and his commitment to it - he's not a 1D maniacal villain (like so many other cbm villains) , but a real believer who thinks he's doing what must be done.
After crashing on Titan, Spidey, Tony and Strange are attacked by Star Lord, Drax and Mantis - after a scrap, they join forces.
Thor, Rocket and Groot arrive at the forge (its a huge space station build around a star) but it's all frozen up. when they enter, they meet a giant dwarf (as in Peter Dinklage but 30 feet tall), who reveals that Thanos arrived well before them, and used the forge to make the infinity gauntlet, before slaughtering all the other giant dwarves and shutting down the forge.
In Wakanda, Cap and co. meet with T'Challa, the plan being to remove the soul stone, so Wanda can destroy it before Thanos arrives.
In Wakanda there's an epic battle between Cap and the other Avengers (Banner in the Hulkbuster), T'Challa and the tribes/Dora Milje against the surviving Black Order punks and Thanos' legions of generic monsters. The monsters are a bit vanilla, really just cannon fodder - but are a lot more threatening than the Ultron drones, or the Chitauri.
Meanwhile, Thor re-starts the forge, and briefly withstands the power of the dying star in order to heat up the metal - Groot uses his arm as the handle of the new weapon. Thor is pretty messed up, but starts calling the new hammer/axe to his hand.
My favorite battle takes place on titan. Thanos shows up, just Thanos and fights all the heroes there, plus Nebula, who manage to restrain him and almost get the gauntlet off him. However, Starlord loses it when he learns Gamora's dead, which allows Thanos to break free.
The resulting fights between Thanos and Strange and Thanos and Tony are great, particulalry the Thanos v Strange fight. But of course, Thanos wins, and severely wounds Stark.
Strange does give Thanos the time stone, so that he spares Tony. But previously Strange had used it to see the future, and the one possible future, out of a million, in which they win. Strange says to Stark (before he turns to ash) that it was the only way, and they're entering the "endgame"
My theory, clearly he saw that the only way they could win was to give Thanos all the stones at that time -which would set into motion the chain of events that will restore the universe in the sequel, for which clearly Tony had to be alive. Thanos also points out that Strange never used the time stone against him , and it was the heroes' greatest weapon (so clearly that's because for the heroes to win he had to NOT use the stone).
Back in Wakanda there's a pitched battle between the various heroes and Thanos' forces, to prevent them from reaching Vision and taking the stone.
Just when the heroes are overwhemed, Thor (and Rocket and Groot) arrive and in a massive power feat, wipes out a big chunk of the monster horde.
Eventually Thanos arrives, and the heroes take him on in a desperate effort to give Wanda enough time to pull free the mind stone and destroy it.
Thanos smashes them one by one, and Wanda manages to hold him off (again, move that lady up a tier) long enough to destroy the mind stone..... but Thanos uses the time stone to move back to just before Wanda destroys it, and takes it.
Thor attacks and buries the bladed edge of the new hammer into Thanos' chest - but as Thanos says, he should have gone for the head, as Thanos snaps his fingers and....
Well, a big chunk of our heroes (Spidey, Star Lord, Strange, T'Challa, Falcon, Bucky, Wanda, Drax, Mantis ) all turn to ash and fade away.
Tony is left, with only Nebula, on titan clutching at the ashes of Spidey (Strange makes that comment about giving Thanos the stone being the only way, and them entering the "endgame" before he fades away).
The last shot of the heroes is Banner (in a damaged Hulkbuster), Thor, Widow, War Machine and Cap, sitting by Buck's ashes - he mumbles "Oh God."
The final shot is Thanos sitting, watching the sunset, a contented smile crossing his face (something he said he would do, to Gamora, during their chat).
Then fade to black and credits, and sombre music.
Post credits is Fury and Hill on Earth, in traffic, they see other people fading away, and then do so themselves, but not before Fury triggers an electronic device (looks like a pager) on which the Captain Marvel symbol appears.