IT IS hard to imagine how a director or cast can top a $1.5 billion blockbuster.
But Joss Whedon and his Avengers have done just that in the sequel to Marvel's superhero dream team.
Age of Ultron is a truly international thrill ride, taking movie-goers around the globe as the Avengers prove they are the world's protectors.
Bouncing around from the Avengers' new high-tech base in New York to South Africa, Eastern Europe, South Korea and small-town America, this super-charged sequel builds on the sturdy foundations of its predecessor.
With so many heroes and supporting characters, it would have been hard to get the balance right.
But the Avengers get a more even billing this time around. Hawkeye (Jeremy Renner), who was sidelined for most of the first movie, plays a bigger role and we find out more about his personal life.
The various relationships between the superheroes provide plenty of comedic moments, another hallmark of Whedon's vision for this motley crew who, for all of their super-human abilities, are dysfunctional.
"Being the Marvel consigliore for the last few years has been really fun," says Whedon.
"In doing so it's important to keep that sort of Marvel ethos of 'Yeah, we're loveable and yes we're messed up; we're funny when you don't expect us to be and we're serious when you don't expect us to be'."
Acting powerhouse James Spader easily slots in to the well-established A-list cast as Ultron, a form of artificial intelligence which is hell-bent on human extinction.
Spader's voice is engaging and emotive enough to bring Ultron to life in digital and robot form.
Many of the scenes are enhanced by the fact that Spader acted all of his lines on set, rather than just recording his voice in a studio.
Ultron acts as bit of a mirror for Tony Stark (Robert Downey Jr), who also believes he knows what's best for the planet and how to protect it from any future alien invaders.
His intellectual connection with Bruce Banner (Mark Ruffalo) has deepened, but that doesn't mean they see eye to eye on how Ultron should be dealt with.
Two new "enhanced" anti-heroes also join the fray.
Elizabeth Olsen and Aaron Taylor-Johnson, who previously played a married couple in Godzilla, are the Maximoff twins.
Gaining their powers through Hydra's illegal experiments, the siblings are out for revenge on Stark, whose Stark Industry-built weapons killed their parents.
There are also great cameos by Andy Serkis (Lord of the Rings, Dawn of the Planet of the Apes), Don Cheadle and, of course, Marvel patriarch Stan Lee.
This is Whedon's swan song. While The Avengers film franchise will continue, he plans to step down as writer/director after the exhaustive demands of Age of Ultron.
He's still part of the Marvel family and will continue to pen the TV series Agents of S.H.I.E.L.D.
Whoever takes over the franchise from the "king of the nerds" will have big shoes to fill.
Avengers: Age of Ultron is in cinemas now.
Avengers: Age of Ultron
Stars: Robert Downey Jr, Chris Hemsworth, Chris Evans, Scarlett Johansson, James Spader.
Director: Joss Whedon
Reviewer's last word: Director Joss Whedon defies the odds by living up to, and in some ways surpassing, the expectations set by his global box-office smash. Age of Ultron is full of action, humour and heart.
Star profile: Elizabeth Olsen
Quirky fact: Is the younger sister of actresses and twins Mary-Kate and Ashley Olsen.
Best known for: Martha Marcy May Marlene, Godzilla, Oldboy.
If you like this movie you'll like these: Captain America: The Winter Soldier, The Avengers, Iron Man 3.
Quote: "I was embarrassed that I even wanted to become an actress because coming from LA, with two older sisters in the business and a mum who had been a ballet dancer, it was such a cliche."
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