The buildup of the MCU Phase 1 came to a head in this groundbreaking film, that brought these heroes together to fight against the invading army of ... Loki, well sort of.
In the very first scene we learn that the villain isn't really the main villain, just someone doing his bidding.
Nick Fury shows up at SHIELD HQ to find the teseract has been "misbehaving" as we're reintroduced to Dr Selvig (from Thor) and Hawkeye who points out that the teseract is a door and that doors open from both directions, which it quickly does, and Loki starts blowing things up, as well as taking Selvig and Hawkeye as his "personal flying monkeys"... no worries, Cap gets the reference.... or does later...
One of the more important scenes that a lot of people might overlook is when Nick is speaking to the "shodowy committee" and we see that they are just bureaucrats and don't really get what should/needs to be done, but still people in a position of power that can cause problems.
The recruitment scenes are good, get the job done, but (other than Nat & Banner) really don't have a lot of emotion. Bringing Cap & Banner onto the Carrier is good stuff, seeing Cap have to pay off his $10 bet with Fury is great bit between "old soldiers".
Thor is drawn in just in his search for Loki, but they make up for that in an really well written scene between Thor and Coulson on the Helicarrier. Helmsworth should have been on an episode or two of, Agents of SHIELD, maybe a two parter with he and Coulson working, just the two of them, good matchup of characters.
Arguably the best scene in the film is the confrontation scene in the Helicarriers lab, when Loki's influence is affecting all of them, and stirring the pot.
"The world is filling up with people who can't be matched." is one of the phrases that Nick uses to justify more movies about hero's that are already there before The Avengers. Who else is Nick talking about? This is probably the biggest hole that they never really address.
This is also when we get that great scene between Cap & Stark when Cap challenges, "Big man in a suit of armor, take that off, what are you?" But also in that scene, Stark shows his latent hate for Cap by calling him "you're a laboratory experiment Rogers, everything special about you came out of a bottle." which anyone knows, that's really the least of Cap, but they put it in to pump up the Star character and tone down Cap. The scene didn't achieve what it should but did some of what they wanted, even if it was bad for the story.
The scene is interrupted by Hawkeye's attack on the Helicarrier. Banner and Romanov fall to a lower level where Banner does his "party trick" and the Hulk is loose on the carrier, just as Loki wanted. The ensuing battle on board splits the team up with Hulk and Thor knocked off but Hawkeye is brought back with a little smack to the coconut.
This also leads to the tragic loss of Agent Phil Coulson (yeah, I know π) as Loki stabs him in the back. Fury uses the incident to motivate the team, and while in deep thought over what happened, Stark gets a revelation... "son of a b*tch", and he knows where Loki is heading.
Another great scene is the dialogue between Loki & Stark, sorry Tony, the threatening... it's a scene where we see Stark playing with Loki's emotions about Thor and then a final line about Coulson. But in here we also get to see the real Iron Man, the nuts & bolts Iron Man instead of that nanotech nonsense.
The battle in New York is outrageous and a great climax for this phase of the MCU, but we see another issue when Cap lands on a police car and tells some police what he needs, the officer looks at him and says, "why should I take orders from you?".... IT'S CAPTAIN FREAKIN' AMERICA... so we have to see him smash some aliens for one minor laugh in the script, not a cool thing.
During the battle, here comes the shadowy committee again, bureaucrats making fool decisions for a fight they aren't part of and don't get, and Nick trying to tell them how foolish they are. We see them again at the end of the film, where Nick pretty much brushes them off, too bad he couldn't do that earlier. We get hints at this committee but overall in the MCU, they really never make a difference either way from here out. One has to wonder, how many were on our side and how many were Hydra. Looking back now, that committee seems like it was pretty useless in the MCU.
An end credit scene finally shows us Thanos, which was pretty cool but it was a bit obvious to begin with, studios let too much slip out before films are released, or many put the whole story into their trailers, not great filmmaking.
In the end, Nick's plan worked, but was it by design or did he get lucky with the Avengers? Did they get along because they could or because they had to? We see some of that answer in a great, and simple, post credit scene of the crew having schwarma (I don't know what it is, but I wanna try it).
The film gets πππ and a half stars out of five, it was great to see the team together, the fight is good, but overall the film doesn't hit as hard as it could have.