The Spy Who Dumped Me: Between the decapitations and lacerations, you won’t be dozing off

What is the most unnecessary of all the unnecessary film genres? You've read the title. You're already there. The James Bond movies were already parodies of themselves and, for all the efforts of Austin Powers, Derek Flint and Maxwell Smart, they required no further sending up.

For shag's sake! This is at least the second such film to reference The Spy Who Loved Me in its title. No more espionage romps, thank you.

Hold on just a moment. For its first hour, The Spy Who Dumped Me suggests that there might be some petrol left in this tank. Aside from anything else, Susanna Fogel's comedy is the most impressively violent ever entry into the genre.

More sham Bourne than bogus Bond, the picture begins with a furiously bone-crunching chase in a grey (slightly racist) version of Lithuania. Elsewhere, heads are blown off, innocent bystanders are lacerated and one villain gets publicly impaled on a spike. You won't be dozing off, anyway.

Dumped Me also succeeds because, before spinning into chaos, it makes good, contrasting use of its two leads. Mila Kunis, endlessly disappointed by life, rolls her eyes vigorously as an organic-food store employee who doesn't know that her boyfriend (Justin Theroux) is really a CIA killer. Kate McKinnon plays a verbose friend who, at some point, admits that she can seem: "a little much".

That criticism could be directed at McKinnon's fidgety, showy performances on Saturday Night Live and the Ghostbusters reboot. There was quite enough winking and arm waving in that last project, but Fogel seems to have sat upon her and allowed a less ostentatious verbal comedy to blossom.

The two actors have plenty to work with in a decent script. "Are you a lover of Balzac?" a deliciously sleazy Fred Melamed asks her. "Less and less with every experience," McKinnon deadpans.

Sadly, in its last act, the picture falls apart like a clown car. As is so often the case in such things, Dumped Me begins to care about its stupid plot and seems to want us to care too. Read the microfilm, guys; nobody gives a hoot about what's on the mysterious zip drive. Worse still, McKinnon escapes the leash and, in a late, over-worked extravaganza, re-introduces too many of her bad habits from SNL.

Still, much funnier than it had any right to be.

Opens: July 22nd