One must at a bare minimum credit Salt for being unconventional: what happens in the second half of the movie, while not exactly "unpredictable", is certainly unexpected, if only because it's just not at all the sort of thing that is done in American studio filmmaking. Part of me almost wants to find a way to therefore praise the film as an avant-garde explosion of the expected tropes of a Hollywood "wrong man" thriller - part of me indeed feels like a bit of a square that I'm having such a hard time embracing it as such. Most of me can't get around the idea that the film just suffers from a massively broken screenplay by Kurt Wimmer (who has written a number of broken screenplays; he also directed Ultraviolet).

It is very nearly saved, and hell, maybe it is saved, but only barely, by two things: craftsmanship and star power. The latter of these is readily observed by anyone with eyes to see, for the title role of Evelyn Salt is played by Angelina Jolie, who remains one of the most arresting and magnetic film actors presently working, even as she has slowed her career down to a crawl these last few years, something about "family" or some such (what Jolie fails to realise is that genuine movie icons of the classical model are a rare and dying breed, and that it is her duty to make films all the damn time so that we can all continuously bask in her reflected glory; but OH NO, she has to be a loving mother as well as a fucking brilliant movie star). It is kind of incredible that the film was originally designed with a male lead in mind (theoretically not named Evelyn), with Tom Cruise often cited as the producers' first pick; by all accounts it took very little tweaking to make Mr. Salt into Ms. Salt, but it's impossible to imagine anyone but Jolie in the role. It does not play to her strengths as an actress - nor to anyone else's strengths as an actress, one must assume, given the general lack of subtlety of the characterisation, and the crude way that the script denies us access to Salt's inner life - but it assuredly plays to her strengths as a bad-ass. Given how very flimsy most of the movie is, it takes a strong anchor to keep it from blowing away, and Jolie's face and presence are very much that anchor. Besides, she has a great gift for throwing herself into action sequences and making it look real and easy.

And it would be disingenuous not to admit that there really is something exciting about seeing a beautiful woman proving she can be just as rough and tumble an action star as any man; there's not much in the film that specifically plays with the idea of a female lead (the opening sequence, in which she is tortured by North Koreans, is probably the most forthright in that regard), but the over-arching notion of "female action hero kicking ass" in a role that doesn't tie her ass-kicking to her femininity in any programmatic way is in its own way the freshest thing to happen to action cinema in ages.

The other side of the camera finds Phillip Noyce directing his first unabashed action movie in over a decade, and his best since helming the excellent middle two Jack Ryan films, Patriot Games and Clear and Present Danger. Noyce's name is not as readily familiar as some of the more recent action masters, but his skill is undeniable, no matter what mode he finds himself working in (earlier this decade he was responsible for the fine Graham Greene adaptation The Quiet American, and even if there's not much to like about his last film, 2006's Catch a Fire, it's not the direction at fault). Without Noyce, it's hard to imagine that there would be a Paul Greengrass; which is sort of fair, because without Greengrass's two Jason Bourne movies, it's hard to imagine that there would be a Salt.

But I shall not generalise: if Salt is conceptually a Bourne clone, it is not stylistically. Noyce, in his infinite wisdom, has found a third way between the aggressive hyper-kineticism of Greengrass and his kin, and the relatively stately action aesthetic that has been dying out by degrees over the last half-decade. As he leads Salt - which boasts fine, if unexceptional cinematography by the extraordinary Robert Elswit (who at the very least knows how to light Jolie to perfection), and a power team of action editors including John Gilroy (of Michael Clayton) and Stuart Baird (of Lethal Weapon, and more recently Casino Royale) - it is a film that combines high-speed cutting and crazy movement with an unusually refined eye for continuity; it is the neo-action film for all those people who considered The Bourne Ultimatum to be upsettingly disorienting. There is no moment that is not well-treated by Noyce's steady hand and careful eye; from an incredible "escape from the CIA" sequence that leads from a locked room to a crazy and physically dubious highway chase, all the way to a thrilling "bunker with a glass wall" showdown at the end.

If I have privileged Jolie for being iconic and a great action star, and the filmmakers for their deft handling of the action, and not said anything about the script; well in this I'm just following Salt's own lead, for it doesn't especially give a damn about the story either. What you've seen from the trailer is about all the further we can go until Spoiler City: Salt is a CIA agent under the direct command of Ted Winter (Liev Schreiber), there's a Russian defector named Orlov (Daniel Olbrychski) who claims that "Evelyn Salt" is the name of a Soviet spy from way back, and an outside agent named Peabody (Chiwetel Ejiofor) decides that this is serious enough to look into the matter. Salt is too worried about her arachnologist husband (August Diehl) to stay around for questioning, which makes her look that much guiltier, and though Winter defends her against Peabody, her decision to travel to New York - where she's allegedly about to kill the Russian president - to presumably clear her name makes her look guiltiest of all.

So far, so good. It's trite, it's clichΓ©d, and it requires dragging out some Cold War nostalgia that makes exactly no fucking sense in the year 2010, but since it's all just the pretext for some fun action, it's really no harm, no foul. But I can't go any further - can't explain why I don't like the movie that I've done so much to praise - without flat-out spoiling the rest of the movie. Even though we're only half-way through, but it's a half that the ads have done a fine job of hiding.

MEGA FIVE-ALARM SPOILER ALERT it is, then: Salt is a Soviet plant, and she does kill the Russian president (if there was meant to be any ambiguity on this point right up until the moment of the murder, as suggested by the tagline "Who Is Salt?", I completely failed to observe it). But her subsequent actions all make it very hard to say whether she's a bad guy or not, and of course the most predictable thing happens ever since Liev Schreiber and Chiwetel Ejiofor both appeared: Winter turns out to be the really bad guy (and another Soviet plant!) and Peabody agrees to help set-up the sequel. And the Russian president isn't really dead. So here's my thing: after setting itself up as an entirely satisfying "wrong man" film, Salt goes nuts in the middle, and suddenly we don't know, until the very end, whether our heroine is a bloodless Soviet killer or not. Man, I still can't get over that - Soviets? Are we really still doing that?

Certain movies can get away with denying the audience key information that the protagonist possesses; Salt isn't one of them. It just plain doesn't work to have the main character of an action movie called into question like that: do we root for her, or don't we? The answer is pretty easily figured out to be "yes", because no summer tentpole is going to have that kind of anti-hero, but all Jolie's charisma and Noyce's directorial mastery - both of which are firmly in evidence through the back half of the 100-minute film, even at its most narratively confused - aren't enough to save the movie from that kind of unnecessary obfuscation of its central conflict. For every bit of 30 minutes, we're along for the ride because we're "meant" to be, not because we have a good reason to be, and that is no way for an action movie to work. As I said, part of me wants to praise Salt for that kind of convention-busting innovation, and part of me recognises that the conventions exist for a reason. It's crazy, given how much of the film works like gangbusters - shallow, summer movie gangbusters, but a rocking good action scene is always welcome - that one script malfunction could ruin the whole thing; but it is a truly dramatic malfunction.