SHEPPERTON STUDIOS, MIDDLESEX - Joss Whedon looked tired.

And not just a little tired, either. He looked weary, deep down in his bones tired. He looked like he was ready to just fall down where he was and sleep for a week. I've seen a number of other directors in this state and it's always when they're near the end of production on one of these mega-movies. The pressure that's on these guys in enormous, and for Whedon, following up one of the biggest films of all time can't be easy.

We sat in a small group facing Whedon in the Tony Stark lab, part of the Avengers Tower set, and asked him what his primary goal was walking into the sequel.

"On the first one, I was a raggedy man when I made that film. It did take a lot out of me. Going in this time, I was like… I just had to recalibrate my entire existence and throw myself into it more wholeheartedly and actually make it harder to make them last, and I'm gonna just invest myself in every part of it… every production meeting, every location scout, and every question about a prop that I'd like to avoid, and I might even work harder on the script. I'm gonna give myself up to it, like a Christian to a lion."

One of the most amazing things we saw during our time on set was Paul Bettany in his full Vision make-up and costume, and we asked Whedon if that was the final look for the character. "We make them as close as we can. The stunt guy, we make allowances for the shape of his face and padding and things that we're putting on him. But they're not meant to look different. Basically, what usually happens is one of the [concept artists] draws something unbelievably beautiful, and we try to create that in real life and it takes a long time. The first tests we did were very Violet Beauregarde. It really took a long time to get to a place where we felt like… we'll do a little work on him in post, but when he walks on, we go, 'It's the Vision. Oh my god.'"

We told him how exciting it was to see him in the make-up. "I wanted Paul to play this part since before I wanted to make 'Avengers' movies. Let's face it. It's all about cheek bones, people." That seemed like he walked into the movies with a plan, and we asked him if that was the case. "Before I took the first job, I said, 'Well, I don't know if I'm right for this or if I want it or if you want me, but in the second one, the villain has to be Ultron, and he has to create the Vision, and then that has to be Paul Bettany. It took me three years before I could tell Paul that I'd had that conversation. I was like 'That would be cool if there's Ultron and you have the Vision and Paul played him and you should have Scarlet Witch and Pietro, definitely." They're from my era. They're very different. Their powers are different. It's not all punching. It gives you a different palette, and we can do more interesting things. It's fun. Those things were absolutes. But I didn't want to make the film necessarily. I was ragged from the first one, so I just turned off my brain. I was like, 'Do not think of cool ideas for the next one. Just get through this.' But after a few months, I felt like, 'This is now something that makes sense in my life. Do I have anything to say?' So my agent called and I was in London, and he said, 'You know, there's a deal that's worth talking about. Time to start to think about whether there's a movie.' And I'm going, 'All right,' and I went to a pub and sat down with my notebook and about forty-five minutes later, my notebook was filled. And I texted my agent, 'Yup. I have so many things to say.' I was kind of surprised. It took me unawares. It was very beautiful."

We asked him if he was setting up things in this film that will play out over the rest of Phase Three and Phase Four of the Marvel movies. "You're aware of that, but you can't be slavish to it. The biggest mistake in the world of franchising is saving it up, like, 'We'll do that next time.' Whatever you want, get it in there this time. Not that we can do everything with every character, but you want to get in an arc that's complete. You don't want people to think, 'Wow, that's part one of something or even part two of something.' I have been lambasted for criticizing 'The Empire Strikes Back," but I wasn't criticizing the film, which I love very much. I was saying that there's something frustrating about the experience of having a movie not end. It's weird for me and kind of disturbing. And for me, I need to get everything in that I need and then, if it continues, either I or somebody else will need more. These characters have existed in their iconic narratives for longer than I've been around, which is just really long."

We asked him how close the final film would be to that first flurry of ideas that filled his notebook. "A lot of them. Some were like, 'This is it. This is the heart of it.' Or 'This doesn't work.' Generally speaking, it's character stuff. It's definitely not plot stuff, because that's the stuff that you pull out of yourself with agony. The character stuff is more like, can these people connect and these people can't connect, and we can tear them apart and bring them together and have this insight into the character. That's the stuff that makes me want to make a film. Not 'Here's a cool plot twist!'"

One of the things they told us during our visit was that Bruce Banner and the Hulk both have greatly increased roles this time around, and we asked Whedon if he told them to hold off on another stand-alone "Hulk" movie. "I wasn't the one who said don't make a 'Hulk' film or anything like that. It was Kevin [Feige] who said to me, 'We think right now it's good to have somebody who we could only have in 'The Avengers.' Everybody loves Mark. He's phenomenal. But the fact that there hasn't been a Hulk since that Hulk… it doesn't suck. My job is hard enough, you know? Cap's had a movie. Thor's had a movie. Everyone's gone through big changes. Iron Man had a movie. I have to juggle everyone's perception of that while still making a movie that you can see not have seen anything since the first 'Avengers,' or not even that."

Asked about the scale of the film, Whedon said, "I don't remember saying it was bigger. I remember saying it was harder. But it is bigger. The cast is bigger. The scope is bigger. We have more to work with. Not that we're trying to spend more. In fact, we're trying to avoid bloat wherever possible. But we're on a broader canvass. We're in more countries. We have a bigger world to work with, and a bigger world for them just to be in. Once they exist as a team, we have to deal with what everybody thinks about that, and what that means to the world. It's not as simple as it was."

One of the reporters asked if there's a Dr. Frankenstein and his monster thing happening with Tony Stark and Ultron in this film. "In the Marvel Universe, there are a lot of Frankensteins. You know? Steve Rogers himself, one of the better-looking Frankensteins of our era. There's always an element to that. There are a lot of people, whether they're trying to do good or bad, who think they have the next big idea. And the next big idea is usually a very bad one."

We asked how he was approaching Hulk this time around. Bruce plays a key role in the creation of Ultron, so it's not just the rage monster we're spending time with this time around, and we asked Whedon if we're going to hear more Hulk dialogue this time around. "His monologue about his childhood is very poignant and lacks all pronouns. No. The talking thing is something that, you know, I sort of… I pitch it and I take it away. It's moment to moment. Done wrong, it could kill you. So I'm pretty leery about that. But Banner has a significant role, and the Hulk… we really held back on him for a long while in the firs tone. And there's something terrible coming that you'll love. And what makes the Hulk so hard to write is that you're pretending he's a werewolf when he's a superhero. You want it vice-versa. You want to see him. Banner doesn't want to see him, but you don't want Banner to be that guy who gets in the way of you seeing him. So the question is how has he progressed? How can we wring changes out of what the Hulk does. And that's not just in the screenplay. That's moment to moment, because you know that even when they are putting in the post mix, they have a library of two roars. What if he wasn't roaring? I'm angry and I'm not roaring. I'm being very polite to a lot of reporters right now, but I'm filled with rage."

We told him how excited we were to see Quicksilver, the Scarlet Witch and the Vision all joining the roster in this film, and asked him if there's an overall explanation for the new proliferation of superheroes. "Baron Von Strucker's been doing experiments, and he's got the scepter, and he's been using alien tech to do them. That's kind of where I landed with that. But look for the exciting ret-con in 'Avengers 6'!"

We asked if it was easier to find the voice of the movie this time around, having done it once before. "Most of them had already played the parts before even the first one, and it's hard not to hear Robert Downey in your head. He's very distinctive. And, you know, it's been easier for me to give them what they are comfortable with, and also to let them sort of mold stuff a little bit, you know? There are certainly things where I'm like, 'If you want to make this more your own in some way that I haven't thought of yet…' We have mutual trust, where if I say, 'I know this feels weird, but I need it,' and they will back me. And if they say, 'I feel like I could come at this differently,' I will back them, because we're creating those characters together. They will always see something that I missed. And they will always have some little insight in there. Especially when all ten of them are in a room, you know? I've got all of these enormously interesting actors playing enormously interesting characters. I'm not going to get every nuance of everybody. And somebody will say, 'Wait a minute, aren't I already dead in this scene? Should I have so many lines?' 'Right. Good point. Sorry.'

As we laughed, he added, "By the way, please don't turn that into a headline. I'm so sick of reading about killing people."

When we asked him how the Scarlet Witch fits into the mold of the strong Whedon woman who is also somewhat damaged by their powers, he replied, "Well, you know, 'strong but damaged by power' describes every person in this movie. It may, in fact, describe what the movie is about. The more power that we have, the less human we are. Her damage predates her power, and these kids, they've had a pretty rough history. Is she an idiom with which I am comfortable? Why, yes, sir, she is.

We asked him if he's been able to bring the various mini-movies within this film together in a way that makes them feel like a satisfying whole. "That was a concern for Marvel for a long time, but a lot of the working out of the story was how do we get these things to connect? I'm not probably going to explain that, but it's very important to me that they do feel like part of the same story, and part of the same universe. And they're all… their origins are all tied up in each other."

We ask if we're going to find out why Hawkeye has been largely MIA during the Phase Two films since the end of "The Avengers." "Yeah. We are. 'Cause something's up with that boy. That's all I'm gonna say."

Well, then. That's a provocative way to put it. We asked about James Spader playing Ultron and about the role that Ultron plays in the film as a character. "Ultron feels a certain distance from humanity, and the day Spader got here, we put on the mocap pajamas, a giant thing with red dots on it for his eye line, and you know, this giant pack and a helmet with two cameras in his face with lights to record his performance. He did a scene with Scarlet, but she couldn't look him in the eye because she was looking up at his eye line, and he couldn't really see her because he had two lights shining in his face and he had his glasses on. Therefore, he has a certain distance from humanity, too. And god bless him, he was wonderful and very game. He has been the whole time, very interested in the mechanics of the mechanics, and in finding the humanity. He and I share a genuine love of this version of Ultron and he has an innate eccentricity in his delivery that is everything that I had hoped Ultron would be."

We asked how he's different from the standard bad guys in superhero movies. "I think for me, there's always a point where I'm writing where, you know… they're right. 'The Avengers suck! Got to do something about that. We got to take care of these guys.' Hopefully, you will come out of this… if not agreeing with him, getting him and getting his pain, which leads to a lot of damage and some humor. How is he different? Hmmm. I mean… villains are different from each hoer. The important thing for me is he's not this external thing. He's not, you know, 'Independence Day'. I'm not criticizing that movie, but I'm saying that it's not like we spent some time on the alien going, 'I hate that Will Smith! He punched me right in the face!' When he's in his scenes, you want to feel like he will never understand that he's not the hero."

We asked him if "Days Of Future Past" caused him to rethink his own approach to Quicksilver, since they beat him to theaters by almost a year. "Not really. There are some things that we now would probably care to avoid just so that we're not… but we were never doing the same version. Obviously at some point we'll go into slow-mo because… you know… that's what is fun about a super speedy guy. What's fun for me about Quicksilver isn't necessarily seeing Quicksilver… it's seeing the Avengers. You know… he's just a very different guy in ours and we're just proceeding as planned."

Whedon went on to talk about how careful he was to navigate a certain tone with a story that is, truth be told, fairly grim. "I'm aware of what we can't do or say. I know that I work for Disney. I know that I want children to see this film and not have nightmares about it. But, um, I understand the parameters and at the same time, I don't know of a place that would let me make a film this personal for this much money. Marvel… I feel like they treat the movies like they treat their comic books, where when a new writer and artist come in, they have their own visual ideas and they respect that. I get to make a movie that's very much about the things I need to talk about. I forget during the whole process, because these character are so dear to me, that they belong to them. When the thing shakes out, it's very much the movie I dreamed of, and that's why I'm back."

We asked him if there are seeds in this movie that can pay off in "Avengers" sequels down the road. "There comes a point in filming where you are writing, filming and editing, and you can't be making a grocery list. I haven't had a good idea about anything else. I'm so excited that I'm wearing underwear, that I got that right today. Every now and then, it'll happen, but right now, we're just past the halfway point, and I'm still finessing and finessing and finessing, and, uh, I got nothing. I do this. I go home. I rewrite. I go to sleep. I do this. I go home. I rewrite. I go to sleep."

And as he wandered away, back towards video village so he could watch Thor and The Vision throw punches at one another, we could hear him as he went. "I do this. I go home. I rewrite. I go to sleep."

"Avengers: Age Of Ultron" is in theaters May 1, 2015.

A respected critic and commentator for fifteen years, Drew McWeeny helped create the online film community as "Moriarty" at Ain't It Cool News, and now proudly leads two budding Film Nerds in their ongoing movie education.