Close Encounters of the lesser kind. Disclosure Day never catches fire

So now the quasi-governmental forces of bastardry are hurtling around the mid-west in a convoy of black SUVs, desperately hunting for Daniel and his backpack of USB drives. And somehow Margaret, who is being wheeled into a hospital for a brain scan at this very moment, might hold the key to everything that Daniel, Jane, their shadowy pursuers, and various other ancillary characters are trying to understand. Or something.

And that, as far as I can explain it, is the set up for Steven Spielberg's Disclosure Day, which has just opened around the world with all the fanfare and marketing you might expect of a genuine summer blockbuster. But, curiously, almost none of the excitement or anticipation.

Disclosure Day could have worked brilliantly as either a flat-out thriller, or as a more cerebral think-piece. But writer David Koepp (Jurassic Park) has got himself stranded between the genres and finishes up with a chase movie that never quite catches fire, and a talk-fest that spends too much time explaining the bleeding obvious. Even the final moments, where Spielberg badly needed a big reveal to send us home in a state of awe and wonder, instead arrive as a fragmented and underwhelming procession of images on blurred TV screens.

Worse, I think, is the film clearly needed more time in the edit suite and the special effects studios. Scenes feels rushed and incoherent, with the narrative connective tissue either missing or barely there. But at the same time the film plods between the set-pieces, and feels unsure of where to head next. While the action sequences - most of which are in the trailers - arrive looking not-quite finished. In a couple of weeks I'm sure the Corridor Crew techs on YouTube will be devoting an episode to Disclosure Day. I'm already betting it will be titled "what went wrong?"

In the leads, Emily Blunt and Josh O'Connor can only do their best with what the script is giving them to work with. Colin Firth is odd, but oddly effective as a black-suited telepathic baddie. And Colman Domingo (Sing Sing) is at least dignified as an underwritten mentor figure who Koepp must once have thought was necessary, and then didn't quite know what to do with.

Even acknowledging a handful of scenes that work passably well, Disclosure Day is a disappointment. It is far too daft to take seriously. But not nearly propulsive and gleeful enough to just sit back and enjoy. For a rumoured hundred million US dollar budget, Disclosure Day should have been either smart, or fun - and preferably both. But the film I saw this week was mostly an over-hyped and poorly conceived slog, which all the star-power on screen couldn't rescue or redeem.

For a fraction of this budget, Spielberg could just have dusted off his mighty Close Encounters of the Third Kind- which Disclosure Day is of course trying to evoke - and released it next year for a 50th anniversary victory lap. Now that would be a couple of hours in front of a big screen I would be happy to experience.

Disclosure Day is in cinemas everywhere.