Marvel superheroes of all kinds from Iron Man to Ant-Man took over Comic-Con this weekend, as leading actors revealed surprises to films that will showcase the characters.

Avengers: Age of Ultron, the highly anticipated sequel to 2012’s superhero ensemble Avengers, brought out a star-studded panel that included Robert Downey Jr (Iron Man), Chris Hemsworth (Thor), Chris Evans (Captain America) and Samuel L. Jackson (Nick Fury).

In 2012, Avengers became the fastest film to cross the $1 billion milestone at the global box office.

The sequel introduces Aaron Taylor-Johnson as Quicksilver, Elizabeth Olsen as the Scarlet Witch and Paul Bettany as The Vision. James Spader will play villain Ultron.

Comic-Con, an annual convention in San Diego that began as a gathering of comic book fans and a home to creative content for fringe and cult audiences, has become a top venue for movie studios to unveil blockbuster projects.

The audience at the Marvel showcase was shown a sneak peek that begins with the group of superheroes joking over drinks. The banter quickly turns to action-filled drama as the superheroes have to reunite to save people from Ultron.

Olsen, one of the two women on the panel for the film, said her character’s use of magic “ends up adding something epic to the fights, it’s a new element”.

Spader said he enjoyed his turn as the villainous 2.4-metre tall robot Ultron, describing the experience as “startling and surprising and challenging and exciting”.

Marvel is releasing Guardians of the Galaxy, about a rogue group of galactic heroes on Friday and the film is already drawing strong reviews from critics and word-of-mouth with fans.

Guardians of the Galaxy 2 was announced on Saturday’s panel as scheduled for release on July 28, 2017, and James Brolin was revealed to be super villain Thanos, entering the stage wearing Thanos’ Infinity Gauntlet.

Also presented was a first look at new film Ant-Man.

The hero is the alter-ego of electronics expert and sometime burglar Scott Lang, portrayed by Paul Rudd, who has the ability to shrink to the size of an insect.

Michael Douglas will play scientist Dr Henry Pym, who invents the ability for humans to change size, Corey Stoll will play villain Darren Cross, who was revealed to be Yellowjacket, and Evangeline Lilly was revealed to be Hope Van Dyne, daughter of Hank Pym.

Fans were treated to a clip showing Rudd as Ant-Man, shrunk to the size of an insect and escaping on the back of a fly.

Daniel Radcliffe goes undercover

Fans posing with a person in a Spider-Man mask at the Comic-Con convention in America may actually have been standing next to Harry Potter.

Daniel Radcliffe, who played the boy wizard in the on-screen adaptations of J.K. Rowling’s fantasy book series, has said he donned a Spider-Man mask at the San Diego event this weekend in order to make his way through the crowds unnoticed.

In an interview Radcliffe said it was a great experience.“I did an American accent for the whole time,” he said. “I even took a rucksack, so I look like I’m just coming to Comic-Con. I had a whole look. But it was great... I took lots of pictures with people who did not know that it was me.”

The 25-year-old said he was delighted to become his favourite superhero character for a few hours during his first ever appearance at the convention.

“I always loved that character. I love the comics, actually, as well,” he said. “I almost got a picture with two girls dressed as Mary Jane and Gwen Stacy, but the moment had passed.”

Radcliffe’s latest film Horns sees him play a character who sprouts horns on his head that are invisible to others but provoke them to confess their darkest truths to him.

From virtual reality to networking, five highlights of the event

Every year, around 130,000 comic book fans and entertainment enthusiasts trek to San Diego’s Comic-Con International, where thousands of booths and hundreds of panels are set up by industry outlets to cater to attendees.

Here are five highlights from the packed four-day event.

Experiencing death in virtual reality

Ever wondered what it’s like to be killed by a giant alien or a blazing fireball? Movie and television studios harnessed the virtual reality capabilities of the Oculus Rift headset to allow fans to enter the worlds of films and shows with numerous simulations.

For HBO’s Game of Thrones, fans could experience actual death – a terrifying experience for anyone with vertigo – as they ‘travelled’ up the Wall and stood at the very top, only to be attacked and fall to their inevitable demise.

In Legendary’s Pacific Rim experience, fans were ‘placed’ inside a giant robot that is attacked by an alien monster.

Homer Simpson stops by

From the giant ‘Homerdome’ of Homer’s head to Marge Simpson’s make-up range launched at the MAC cosmetics store, Fox’s hit animated television show The Simpsons celebrated its 25th anniversary by making appearances throughout the convention. On Saturday, show creator Matt Groening was joined on stage by a life-size hologram of Homer making quips about the convention, Stephen King and making Groening do a little dance.

Stepping into Mockingjay

Mockingjay – Part 1, the third instalment of The Hunger Games franchise, was recreated in part with Samsung Galaxy to allow fans to step into the stark world of Panem.

An all-white room provided activities from making customised T-shirts to sitting in President Snow’s chair and trying baked goods from Peeta’s Bakery. The film’s latest trailer also premiered during the convention and fans were able to watch it on tablets in comfort in pod chairs.

Star power

Despite a much more muted Comic-Con in comparison to 2013 – not surprising given that last year, the studios brought together major ensemble casts such as those of X-Men: Days of Future Past, and The Hunger Games franchise – there were still some fan favourites in attendance.

Benedict Cumberbatch and Daniel Radcliffe both made their Comic-Con debuts, Matthew McConaughey dropped by the Paramount panel to chat about Interstellar, and the superheroes of Avengers: Age of Ultron including Robert Downey Jr, Chris Hemsworth and Chris Evans added star power to the Marvel film panel.

Glitzy industry networking

While Comic-Con is a haven for comic enthusiasts, it is also an opportune place for high-powered industry shindigs. The cast of A&E’s horror show Bates Motel mingled with Playboy bunnies at a party that looked like the inside of the iconic motel and NBC hosted a rooftop soirée with stars of Constantine, Grimm and Hannibal.

Entertainment Weekly’s annual celebration hosted Comic-Con’s high-profile attendees, including those from The Hobbit, Game of Thrones and American Horror Story, who mingled over drinks and a photo booth session featuring the Iron Throne from Game of Thrones.