Watching the latest Avengers film might be compared to setting fire to a big bag of fireworks - sure, you know it's going to be spectacular, and you can be pretty sure that someone will get hurt (probably the third extraneous character introduced, and the only one who is given a back story), but it's over quickly, and it doesn't leave you with much to think about.

I guess that's both Age of Ultron's greatest weakness, and its greatest asset. It's mindless. Utterly mindless. When it's described as 'the latest instalment in the Avengers franchise', that's a surprisingly comprehensive description. It doesn't do anything more than it has to. You know that Tony Stark will swan around a glass building, interfacing with his computers and saying words that sound vaguely sciencey. Black Widow will brood. HULK SMASH. The film doesn't dip a toe beyond the house style.

At one point, to the film's credit, it almost turns to introspection. For a minute, it looked like it was going to explore the issue of the hundreds of people who are written off as collateral damage in the Marvel universe. The people who are squashed every time Stark and co. careen into an office block. But then Stark and co. careened into an office block, and the action continued.

And what a lot of action there is. Between the destructive, and strangely bloodless, fight scenes, all of the different characters claw and scramble for a few more minutes in the spotlight. It's a zero-sum game, with all of the different strands - the blossoming romance between Banner and Romanoff, the revelation of Hawkeye's hidden family, and the Cap'n pouting with regret - jostling for attention, and, as a result, feeling grossly underdeveloped.

There are some nice interludes to the mania. There's a fun cameo from Andy Serkis as an arms dealer with an almost South African accent, and a stunning bit of animation where Robert Downey Junior hallucinates a giant black and gold flying pleiosaur-spaceship-hybrid-thing. But overall, the film is a forgettable spectacle - slickly-produced and cohesive, it glides over the audience, like the ghost of some teflon.

So, whether you'll enjoy the latest window into the Marvel universe really depends on whether you enjoyed the previous one. Either way, don't worry - you will have forgotten all about it by the next morning.