There's never quite been a movie constructed like The Avengers.  No major mainstream movie (or at least none I can think of) has ever been both the sequel to and the cross over of three different franchises.    Furthermore, this vision has not come from a single writer or director but rather from a studio who wants to translate their business model for comics on to the big screen.  That model demands that characters and plotlines carry over between different stories and therefore the consumer must draw from multiple products in order to understand the larger narrative.  However, each story contributing to the collaboration must also stand on its own.But there's been a cost to this ambition and that cost has been felt in the plotting of Iron Man 2, Thor, and Captain America: The First Avenger.  We normally feel miffed if a film provides a presumptuous cliffhanger but these three films have gone one step further by gearing elements of their plot towards a final product.  Has Marvel damaged three movies in order to build the biggest superhero movie of all-time?  Hit the jump for more.[This article contains spoilers for Iron Man 2, Thor, and Captain America: The First Avenger.  You've been warned.]I was slightly surprised yesterday when Paramount released part of the ending to Captain America and ten seconds of Avengers footage that plays after Captain America's credits.  First off, I've never seen a studio post the ending of their movie while that movie was still in theaters (and not even in theaters for a week!).  It's not the full ending and maybe Paramount just assumed that they weren't spoiling too much since set photos had leaked out last year.  But then they attached The Avengers teaser and that's a little odd since Disney owns that film.  It's bizarre that Paramount would help to sell their competitor's film unless Paramount owns a stake in The Avengers.But the release of that footage highlights the fact that Iron Man 2, Thor, and Captain America have never really been their own movies.  They're prequels to a film that doesn't exist yet.  You could argue that all previous movies in a planned anthology fit that description but usually the first film must stand on its own and it's the job of the following films to build from there, not vice-versa.  Even prequels in the conventional sense refer to an initial movie that audiences have seen and then the filmmaker tells an origin story to get us back to where we know we're going.Not knowing the final destination, or at least the details of the final destination, has resulted in some confusing and unfortunate decisions that feel forced upon The Avengers lead-up movies.  For example, Iron Man 2 has to take periodic breaks in its two-pronged main story (Tony Stark dealing with his Palladium poisoning and having to deal with Justin Hammer/ Ivan Vanko) to awkwardly weave in Nick Fury, Agent Colson, and Black Widow.  The movie manages to pull it off but it takes a story that's stretched thin and then forces it to handle more elements.But cutesy winks to the audience let us know that Jon Favreau and the screenwriters didn't know the details of future films.  It makes no sense when Tony Stark picks up Captain America's shield in Iron Man 2 so he can prop up part of his laser-beam device thingy, but we didn't know that last year.  Last year we assumed that the shield had somehow found its way into Howard Stark's old personal effects.  But this year we learned that the shield had been frozen in ice with Captain America.  There are two possible solutions here: 1) The shield Tony Stark has is a prototype shield that's not made of Vibranium*, or 2) The plot of Captain America was still being hammered out.  If it's the former, then shouldn't someone in either Iron Man 2 or Captain America at least note that there's a prototype?Thor makes S.H.I.E.L.D. a much larger element of its plot but even that feels like somewhat of a detour.  Time that could have been spent developing the relationship between Thor and Jane is spent having S.H.I.E.L.D. take Jane's stuff, puzzle over Mjolnir, Thor sneak into the base, try to get his hammer, introduce a new Avenger, and then they give Jane back her stuff when it would have made more sense simply to recruit her and provide her with more resources for her research.  But since Thor is a mystical character he has to have a more "realistic" connection to the struggles of Earth and I suppose the thinking was that S.H.I.E.L.D. would help ground the Norse god.And while fanboys got a thrill seeing Jeremy Renner as Hawkeye for the first time, what do you think if you're not acquainted with the comics or how The Avengers is being constructed?  I can't help but wonder if the uninitiated were watching Thor and thought, "Why is Jeremy Renner up in the air with a bow and arrow?"Captain America works the best for the majority of its runtime and yet gets saddled with the worst of The Avengers preparation. Because S.H.I.E.L.D. doesn't exist in 1943, there's no one to swing by and disrupt a, good, old-fashioned adventure story.  The movie largely gets to exist on its own terms.  There's the Cosmic Cube that was introduced post-credits in Thor, but you don't have to see Thor in order to understand, "This is a mystical doo-dad that can be used as a weapon."Where the story suffers is in the ending.  Instead of allowing audiences the opportunity to see more films of Captain America fighting in the 1940s, the film has to get him to The Avengers.  Someone at Marvel must have thought that audiences may be confused if there's a gap that doesn't show how a guy from the 1940s wakes up in 2011 and hasn't aged a day.  Personally, I think audiences could accept Steve Rogers and Peggy Carter going on a date and then the next scene has Cap' waking up in 2011 with audiences wondering how he got there but eager for the sequel to find out.I would like to think that a post-credits scene in the lead-up movies could have sufficed as the contribution to The Avengers.  If you were to knock out all of the S.H.I.E.L.D. stuff in Iron Man 2 and Thor that doesn't come after the credits, would you lose anything truly essential to selling an upcoming film? Do you need a vague introduction to Hawkeye or a reminder that Nick Fury is putting together a team of superheroes?  The Incredible Hulk and the first Iron Man worked just fine with only an end-credits sequence and a slight wink to S.H.I.E.L.D. so why has the organization (and therefore The Avengers) keep looming larger in each movie?  I’d like to think that someone at Marvel was thinking, "This is to show the growing power of S.H.I.E.L.D!" but it feels more like "The Avengers: May 2012!"All of the lead-up films have had to sacrifice so that The Avengers can live** but then The Avengers has to pay back that sacrifice by hitting the ground running.  There can't be recaps, there can't be lengthy reintroductions, and no awkward exposition beyond an off-handed joke that references an earlier film.  But will we get that?  And furthermore, how much will The Avengers be its own story before having to build into Iron Man 3 and Thor 2 which are due out the following summer?  And then do those movies have to build into The Avengers 2?Everything is working backwards and there may not be a fully-formed master plan in place.  New directors get hired, writers are used interchangeably, and we can't simply assume that Marvel is like some kind of grand deity that makes sure everything happens for a reason.  It's a balancing act that requires the acknowledgement of a future film and yet they can't simply be a collection of hints, winks, and nods to a movie that only exists in our imaginations.  Marvel also has to walk the line between obsessive nerds like me and the general audience who want to see a fun summer movie but may be left wondering why Clark Gregg keeps showing up.I don't think Iron Man 2, Thor, or Captain America are bad movies.  I don't think the S.H.I.E.L.D. stuff sinks those movies.  But I do think that if each movie had done a better job handling their Avengers preparation, then Iron Man 2 and Thor would go from good to great***, and Captain America would go from great to excellent.  I hope the sacrifice has been worth it because it's not enough to simply get a movie filled with superheroes we've already met.*Now I can't shake the feeling that Colson tells Stark that it's a prototype, but I don't have a copy of Iron Man 2 to double-check so I'll put in a correction if it turns out I'm wrong.**Which is funny since Iron Man and Captain America both feature a father figure who sacrifices himself so that the main character can be a superhero.***Tweaking the ending of Thor wouldn't hurt either.