Last week, we asked readers to submit questions for the actor Matt Damon, whose new film “The Martian” premiered at the festival. He sat down with us at the Ritz-Carlton to answer some of them. Here are his responses:

Q. When will you write a new script with Ben Affleck? — Melanio Flaneur, San Diego

A. I wish I knew. I would love to do that. I wrote one a few years ago with John Krasinski and it was really a blast. The one thing about writing is that it’s very time consuming. And the only way to do it is when you’re basically in the same place as your writing partner.

“Good Will Hunting” was really easy to write for us because we were unemployed. And nobody was waiting for it either. It’s not like we were on deadline. The world didn’t care.

Now it’s just more of a scheduling issue for us. He’s directing something he’s starring in, and then he’s got another Batman movie. And with those, I think he knows what he’s doing until 2020.

Have you talked to Ben Affleck about his role as Batman? Feelings? Sean-Andrew Zeus Pyle, New York

It was obviously a big decision for him to make, but I think he did it exactly the right way. It wasn’t about whether or not he was going to play Batman, it was about whether or not, with the team they had in place, he could make a great Batman movie. Because he got Chris Terrio on to do the script, I think that changed everything. And Ben’s a big believer in Zack Snyder. So when those pieces started to come together, it was a different conversation.

In which of the many movies that you have made did you feel that you learned the most about acting from the director? — Jean, Chicago

Every single one has been a big learning experience. Coppola, who directed “The Rainmaker,” came from the theater. He did a lot of big productions in college. So he had an incredible understanding of actors. When you would turn up at work in the morning, he would gather the actors in a circle and do acting exercises. I’ve never seen a film director do that since. But it’s a huge part of his whole process.

It’s breaking you down and getting you to leave your ego aside. It makes you a part of the group, allows you to embarrass yourself in front of your colleagues in a way that turns the whole day into something really playful. There’s just this implicit support of risk-taking among the artists.

Who has the best Boston accent in movies? — Sawyer, Arlington, Mass.

Ben’s is really good in “The Town.” Ben’s got better. His improved. He worked more in Boston than any of us, so by the time he got to “The Town,” it was pretty flawless, down to the breathing.

What is good for you about playing a hero? A villain? — Sue, Mass.

Well it’s more liberating to play a villain because you can really do anything you want. It gives you more of a chance to play. As the hero in a movie, you do have to keep the audience in mind. You can’t lose them. They need to know why you're doing what you're doing because your job is to hold their hand through the story.

I always thought of myself as a character actor, and the leading man stuff doesn't come as naturally to me. While they’re letting me do it, I’ll do it as long as I can. But I’m really hoping I’ll end up as just a character actor again.

On “The Martian,” how much did you get to geek out with consultants on the sci part of this sci-fi movie? — Liz, Seattle

It’s pretty straightforward, actually, the stuff in the script. Basically, he needs air, water and food, and he thinks of things in those terms. And in the book, Andy Weir started this proposition of, could a guy survive on Mars if he was really well-trained and got a little lucky? Then he said he just let the science dictate everything.

In terms of our consultants and NASA, it was about the science being rigorous. Because once you decide that’s your premise, you have to be kind of loyal to that. You can’t cheat.

Do you think that we’ll put a man on Mars in your lifetime? — Pascal, Maryland

I hope so. We have to get some of us off this planet.

If you were not allowed to act, and were able to do your working life over again, what career might you consider? — Chris Pollasch, Redding, Calif.

I’d direct. And still write too. There’s so much overlap in all those jobs, that I’d still do something to do with filmmaking.

Would you say there are less opportunities for the smaller art film today? — Richard Scott Calif.

The ’90s was really exciting in terms of indie film and was really the heyday. There’s just so much more fear now. The market’s been cut in half. So it’s very hard to get stuff made. When we did “Behind the Candelabra,” no studio would do it. That's Soderbergh directing and Michael Douglas and me. And we made the movie for $23 million.

Ten years ago, that’s not a very big budget for that movie. The good news is we could still make the movie we wanted to make. We did it on HBO. But Steven said to me then, if we were doing “The Informant” today, we’d be on HBO.

Because there’s no market for that $25-$35 million movie about people talking to each other in a room. It’s just prohibitively expensive.

Is there any actor/actress you would like to work with but haven’t yet? — Megan, Dorset, England

There’s a ton. Tom Hardy I think is really interesting in everything he does. I’d love to do something with him. I’m about to work with Alicia Vikander for the Bourne movie, which I’m really excited about. And Tommy Lee Jones is in that too. He directed me in a cable TV movie 21 years ago, but I haven’t really hung out with him since then. But he’s as good as anybody working, so I’m looking forward to that too.

— Mekado Murphy

One of the actors whose performance has generated the most buzz at this festival is also probably the youngest: Jacob Tremblay, who is 8.

He co-stars with Brie Larson’s in the Irish director Lenny Abrahamson’s harrowing, mesmerizing film “Room,” about a young woman who spends seven years in a soundproofed garden shed imprisoned by a sexual predator, which led to her having a son, Jack, who in the film has just turned 5. After “Room,” recently showed at Telluride, Variety //variety.com/2015/film/in-contention/room-jacob-tremblay-telluride-1201586925/ suggested Mr. Tremblay should be part of awards chatter. And a screening here in Toronto on Sunday night, which held the audience tearful and rapt, prompted a writer at Entertainment Weekly to ask if Mr. Tremblay was “this year’s Quvenzhané Wallis.” https://twitter.com/JeffLabrecque Distributed by A24, the film is set for an Oct. 16 release.

Speaking briefly onstage after the screening, along with Ms. Larson, Mr. Tremblay, as well as Joan Allen, who plays Ms. Larson’s mother, and Emma Donoghue, who wrote the best-selling novel upon which the film was based and adapted the script, Mr. Abrahamson said he searched “all over North America” to find Mr. Tremblay. And Mr. Tremblay, asked what Mr. Abrahamson was like to work with, announced, “He’s not a bossy director.” And how were Ms. Allen and Ms. Larson to work with?

“They’re two really nice people,” he said. “They’re two good co-workers.”

Ms. Larson piped up, “I can’t believe we called each other co-workers.”

The heart of the film lies in the unshakable bond between Ms. Larson’s character, Ma, and Jack. To prepare, Ms. Larson assiduously researched the trauma Ma would have undergone, and how it would be manifested, as well as the impact of the physical privations: lack of vitamin D, poor nutrition, not having a toothbrush. And then she had Mr. Tremblay spent about two weeks in “room,” which is what the cast ended up calling the space too, sometimes with Mr. Abrahamson there, oftentimes not.

“We’d just go in room, hang out, play,“ Ms. Larson said, "We had a really awesome time together and I enjoyed spending time with him.” Asked if he had any siblings and missed them on set, Mr. Tremblay replied that he had “zero brothers” and two sisters, one older and younger, and that they visited him at Halloween, and also for “two weeks or one,” adding, “It was a long time ago.”

Ms. Larson smiled at this. “It was December,” she said. “A long, long time ago.”

— Cara Buckley

“Your characters are always dying or they’re getting divorced.”

Julianne Moore recalled her daughter passing that judgment on a movie career that has included about 60 feature films, and more than a few characters who were, indeed, in dire personal straits.

Ms. Moore, who spoke in a staged conversation here on Friday morning, plays a character pointed toward marital collapse in “Maggie’s Plan.” That one is directed by Rebecca Miller and screens here on Saturday, and is for sale at the festival’s associated film market.

In another screening on Sunday — no spoiler here, since it’s a real-life story — Ms. Moore dies, of cancer, in Peter Sollett’s “Freeheld.” Set for release by Lionsgate on Oct. 2, it is a lesbian romance that will have its world premiere at the festival.

The real nexus, Ms. Moore explained to an warmly receptive audience, isn’t so much a taste for misfortune as an irresistible urge to deal with “what is real and within the realm of my experience.”

Describing her response to the sort of character she plays in “Maggie’s Plan,” Ms. Moore said, “Oh, my gosh, those people have been married for a long time and it’s all going wrong, I know that.” She is supposed to be a slightly monstrous mother and professional academic from Denmark.

“She’s not monstrous,” she’s just Danish, said Cameron Bailey, the Toronto festival director who was quizzing Ms. Moore. “And she has tenure at Columbia,” Ms. Moore added, by way of apology for the character’s seeming severity.

In “Freeheld,” Ms. Moore plays Laurel Hester, a New Jersey police detective who, before dying, waged a fight to have her survivor pension benefits paid to a domestic partner, played by Ellen Page.

Ms. Moore called the film a “celebration” of legal and political triumphs in the realm of gay civil rights over the last year. But she also stressed the personal nature of its story, and her relationship with Ms. Page, who played Ms. Hester’s lover, the real-life Stacie Andree.

“I really liked her, and I think she really liked me,” Ms. Moore said of Ms. Page.

“We were partners right away.”

— Michael Cieply

There was bloodshed, mayhem, killer chickens and Patrick Stewart at the first of the festival's Midnight Madness screenings.

Those staying up late for this energy-charged series got a taste of the bizarre in the short film "The Chickening," a parody of "The Shining" that appropriates footage from that film for a funny, yet unnerving beak-heavy companion piece. Its directors, Davy Force and Nick DenBoer, sported chicken ties for the screening.

The main event was Jeremy Saulnier's "Green Room," a nasty thriller about a punk band that takes a gig it wishes it hadn't and must face down a group of neo-Nazis headed by Patrick Stewart. Anton Yelchin, Imogen Poots and Alia Shawkat also star.

When one audience member asked whether it was coincidence or design that the hero (Mr. Yelchin) and the villain (Mr. Stewart) were "Star Trek" alums, Mr. Saulnier simply answered "yes."

— Mekado Murphy

The Toronto International Film Festival, known as TIFF, turns 40 this year, and even though it’s officially middle-aged, it remains one of the hottest film festivals on the continent, as well as the biggest: Last year it drew some 375,000 attendees. But size alone is not what makes it important. Here are five reasons Toronto matters so much:

1. The Timing

TIFF is considered the major launchpad for the awards season, starting on the first Thursday after Labor Day. Fall is when studios generally introduce the films they plan to build Oscar campaigns around. Heavy-hitting contenders often open a few days earlier at the smaller Telluride Film Festival, where “Birdman” had its premiere last year. But Toronto is where films get a global platform. That was the case for “The Imitation Game” last year.

2. The News Media

In 2014, the festival doled out some 1,200 media credentials, and studios take advantage of having stars and journalists in one place by holding junket after junket. “It’s like a worldwide gathering point,” one studio publicist said. “With all the international press and the casts there at once, a lot can be banked for the remainder of the season.”

3. The Location

For East Coasters and Europeans alike, this Canadian city is an ideal destination. It helps that everyone speaks English, and the festival’s thousands of volunteers are as friendly and helpful as can be, happily ushering film lovers through the city’s squeaky-clean streets.

4. The Films for Sale

For distributors, TIFF offers an embarrassment of riches in films, large and small, to pick from. For filmmakers, the festival serves as a world marketplace in which to sell their wares. Nearly 400 titles screened there last year. Among the 2014 deals was Sony Pictures Classics’ acquisition of “Still Alice.” Its star, Julianne Moore, went on to win an Oscar for her performance in it.

5. The Star Wattage

A-list celebrities are there in force, flogging their films. Among the famous people who graced TIFF last year: Al Pacino, Dustin Hoffman, Robert Duvall, Channing Tatum, Steve Carell, Benedict Cumberbatch, Eddie Redmayne, Laura Dern, Reese Witherspoon, Naomi Watts, Mark Ruffalo, Robert Pattinson, John Cusack and, delightfully, Bill Murray, who was celebrated with his very own Bill Murray Day.

— Cara Buckley