All fluff, no substance.

Rating: 4/10 (2 August 2018)

There are movies that have a lot of car chases and explosions and stunts and special effects, but the story is weak and contrived. This movie is kind of like that. It's crap with star power. I will say that it was cool to see so many heroes in a single movie, and there were good special effects and lots of explosions. But, geez, the plot was so weak and contrived!
This is what I call "dumbed down" writing as found in Maverick, a 1994 western about a gambler in a poker tournament. The buy in per player was $25k! In today's money, that's about half a million dollars, for the buy in, not the prize!
DUMB! The writers knew this, why not fix it? Because they think people are too dumb to understand that $1k was a huge amount in the Old West, so they dumb down the writing for them. I hated this, and it ruined that movie. A:IW commits the same sin, more than once.
First, consider the Infinity Stones -- 6 stones created at the Big Bang of the Universe with unmatched power, supposedly. Yet 2 of them belong to Earth heroes? (Vision and Dr. Strange). And the rest all seem to be in our corner of this one relatively small galaxy. With more than a billion trillion stars in the Universe, this is STUPID.
Next, let's consider Thanos' motivation. He grew up on a planet where overpopulation led to collapse of civilization, so now he is on a crusade to ride the Universe of overpopulation by killing exactly 50% of the people Universe. Does anyone else think this is too idiotic? I mean, sure, people on a planet with no space travel and limited technology might overpopulate that planet to the point of self-destruction, but, like, the Universe is full of empty space and empty planets. Like, billions, maybe trillions, of empty planets. And under-population can cause societal collapse, too, right? Insufficient genetic variation and such. Oh, and overpopulation is often a self-correcting problem because as resources get more scarce, people fight more over them and kill each other off.
Not pretty, but effective and largely unavoidable. Thanos' motivation is so stupid that, in fact, one would expect the other characters who discussed the motive to note the stupidity, BUT THEY DON'T! Everyone acts like it is reasonable if cold and heartless. NO IT'S NOT REASONABLE!!!
If you really want to know how dumb this is, consider that the human population doubles about every 60 years. Assuming our growth is average for other intelligent species in the Universe, that means Thanos literally just set back the "problem" of Universal overpopulation by 60 years. And I think he spent hundreds or thousands of years on this master plan? Anyone see the problem? Bueller?
Next, the plot is based on the fact of how infinitely powerful these six stones are, so any hero with just one of them is thereby one of the most powerful superheroes of all. With only 2 stones, Thanos lays out the Hulk with one punch -- the Hulk who held his own against Thor (and then some) in Ragnarok. Then with 3 stones, Thanos defeats the GOTG the blink of an eye. Then with 4 stones... he suddenly has trouble against Iron Man and Starlord? with three stonesBut later, when Thanos has 4 stones, he has trouble knocking out Iron Man, Spiderman and Dr. Strange? And after getting all 6 stones, we learn Thor could have defeated him if he went for a head-blow with his new axe? (The axe trumps 6 stones? Why was Thanos not collecting these axes instead?!)
Next, everyone hero Thanos fought, it was like he had a man-crush on him, gushing how much he respected him. Over & over & over. A transparent attempt to explain away Thanos -- the most ruthless and villainous person in the Universe -- sparing hero after hero (until the very end when he wipes out half the universe, thereby setting back overpopulation by 60 years).It makes no sense for Thanos to spare these heroes he could easily kill in fight after fight after fight. He spares Thor (twice), spares Iron Man, spares the Guardians of the Galaxy at least once, spares almost every hero he encounters in Wakanda. Dumb/fake.
Next, it is a common flaw in most of these "multiple superhero" movies for the authors to complete punt on any logic to the relative strength and power of the respective heroes. I mean, Captain America is basically just a human juiced up to be, maybe, 10 times stronger than a normal person? That leaves him about a thousand (or maybe a million?) times weaker than Thor or the Hulk or Iron Man. And don't get me started on Hawkeye and Black Widow -- totally normal humans who happen to have some martial art skills. Yet in Age of Ultron with a horde of metal robots patterned off Iron Man's technology, somehow every single one of them is pretty much equally kicking ass. In reality, Hawkeye and Black Widow should have been killed by the first robot they encountered, and Captain America would have been killed shortly thereafter.
To see a variety of comic book heroes fighting side by side despite their different power levels, we have to accept this kind of inconsistency. Fine, to a point. IMO, the Avengers movies up to this point did an okay job not going too far ignoring the reality of the power differentials of their heroes. But this movie chucked any realism out the window, then ran outside and pissed on it. We are to believe one of Thanos' top aides -- the woman with the horns -- has trouble defeating a human with no powers just some martial arts skills (Black Widow)? And sure, maybe Captain America is 10 times stronger than a regular human, but Thanos' four-armed, fang-toothed soldiers looked at least 10 times stronger than a regular human, too, so Captain America should not have been decimating them like he was Superman. Oh, yeah, in a big budget Hollywood movie, the "hero" can always effortless defeat an infinite horde of faceless creatures, without any explanation needed.
With all the repetition of how infinitely powerful the six stones are together -- so strong Thanos can kill half the universe instantaneously with just a thought! -- how is it that some space dwarf can forge an axe that can take him down? By the same token, if the six stones are each infinitely powerful, how can one human O.D. on gamma rays or build a metal suit of armor & suddenly be a power match for some one with an infinity stone? (recall he Hulk having his way with Loki when Loki had an infinity stone in his staff)
In fact, Iron Man's power is just plain stupid because from GOTG we know humans are, like, thousands of years behind in their technology. So even if Stark was a visionary building Iron Man's suit well ahead of Earth technology, that might mean it is 50 years ahead, still thousands of years behind those space-traveling alien races. I mean, to Thanos, Stark's technology must be like the steam engine is to us... Yet Stark can go toe-to-toe with Thanos? Makes no sense.
Next, a common stupidity in superhero fighting in general: If a hero has near invulnerability, like Hulk, Thor, (or villains like Thanos), so that they might fall thousands of feet, crash into the ground, and then just get up and brush themselves off, then it necessarily follows that pickup on a giant piece of the ground and smashing it into that person will not hurt him either. Writers often act as if an object ,that would not hurt a superhero who flew into it, WILL hurt the hero if thrown at that hero by an enemy. No, no, no! If Superman can fly into the a train at 500 mph and not get hurt, then a villain picking up said train and throwing it at Superman at 500 mph cannot hurt him either. In effect, this fact would make fights between these near invulnerable heroes pointless and boring, so writers ignore this, but it still is dumbed down writing.
Getting away from general superhero movie criticisms, and back to this movie, a lot of the scenes were just not that fulfilling. When some of the heroes managed to put Thanos to sleep and were about to remove his infinity gauntlet, Starlord suddenly starts hitting Thanos and demanding he tell him what happened to Gematria, so he wakes up before the gauntlet is removed.
Dude, with half the population of the Universe at risk, you can't hold yourself back from interrogating him just 60 seconds till the gauntlet is off??? Then you can waterboard Thanos all you want for information!!! Seriously? The writers want me, as an audience member, to feel satisfied with that story line? STUPID WRITING!!!
Almost as bad was the defeat of Thanos crony who controlled metal like Magneto. They blow a hole in the ship wall and he's sucked into space. Seriously? Can't he just use his power to float some metal to him, grab it, and then float it back into the ship like a buoy? Or maybe float the whole metal ship to himself? Or just seal up the metal hull of the ship before he gets to it? It seemed like the most lazy way to resolve that fight, not even trying to be clever or believable. Why not have the bad guy slip on a banana peel and hit his head, just as original and plausible.
Should we ponder again how Thanos with 2 stones easily beats Hulk, Hulk beats Thor (in Ragnarok), and Thor at the end is just about a match for Thanos with 6 stones? This will never make sense, and it is lazy and poorly thought out writing.