Is Iron Man universally loved because it started the universe or is a good movie? Well it works either way for me, Robert Downey Jr's portrayal was utmost flawless and the irony of the movie couldn't get better. With several references from S.H.I.E.L.D. agents and Nick Fury himself, one could just arrive to the fact that Marvel Studios had planned something big right in the first place. Here are a few examples that show several connections between the major team-ups and standalones.
1. Iron Man Vs Iron Monger + Hulk Vs Abomination = Hulk Vs Hulkbuster.
Iron Man faces a villain with a one hundred times more efficient suit than him, at least in performance if not upgrades, while Hulk goes head to head with a darker version of his character. This is totally what they become in the Avengers: Age Of Ultron!
2. What if I told you...there were some 'so called' plot holes in The Avengers that were already explained before? Well, you probably might have figured them out anyway but that doesn't change the fact that they are still regarded that way.
I could have sworn to have read somewhere that Joss Whedon stated the Avengers would involve some moments from its Phase 1 predecessors.
It does make sense that Thor was unable to lift Mjolnir for a short while in The Avengers.
In the first case, he had temporarily lost his worthiness of possessing its power while in The Avengers, the cell might have created a temporary side effect (just a guess) or they might have wanted to add a reference to 2011's Thor. Maybe he didn't want to pick it up initially while thinking of his irresponsibility by letting Asgardian forces rule the Earth, which is also a potential reference to 2011's Thor.
The fact that Hulk is first full of rage but is then able to control his anger isn't a plot hole at all!
Honestly, you guys shouldn't have this doubt if you've seen The Incredible Hulk. Even Joss Whedon mentioned there are two versions of Hulk, the one where he's out of control and the one where he's stable. This is probably another comic book reference that was originally set up by The Incredible Hulk in the MCU.
Other near similarities...
This scene kind of reminds me of the final encounter of Iron Man 2 where Tony is chased by Whiplash's drones.
While Cap indirectly buys the $10 bet after Fury tells him the world has changed since his disappearance, here's one scene that looks similar to the training scene in his solo movie.
3. Tony Stark/ Iron Man shuts down Stark Industries to protect the people he'd put in harm's way, including the Maximoff twins.
So the twins hold Stark responsible for their parents' death cause they saw a missile with his name on it? Well...what if I told them about...
4. Evolution of Captain America.
It apparently seems as though Captain America's fight sequences will evolve as he progresses from movie to movie, and this is probably one of the things that Winter Soldier gets damn right, and sets up a significantly better sequence in Age Of Ultron. Say, Captain America once jumped from a motorcycle to take down a jet but now he literally throws it on the bad guys.
Might wanna skip to 0:27 to analyze the difference.
5. Black Widow and Hulk's romance in Age Of Ultron actually made sense, regardless of countless viewers that were pissed at it!
Just in case none of you remember, who was with Bruce Banner when he first accidentally transformed into the Hulk in The Avengers? How did she react to it?
This is more of a setup to a team-up movie from a team-up movie itself.
Well it wasn't much of a setup to a relationship but it did make sense. Even in Age Of Ultron, she was initially used to calm the Hulk down and mentions that Bruce Banner saved her friend from being a treasured memory. It was rather professional than personal. Keep in mind that she fits into any type of cover she's in. Even when she gets so much as close to "I adore you", she deliberately pushes him into a huge pit saying "But I need the other guy." When you cage the beast, don't let it get angry.
6. Another major similarity would be 'getting even' with the Hulk.
Now they're even!
I'd say the Avengers movies were pretty much set up by every MCU predecessor (Except Guardians Of The Galaxy). Let me know what you think!