CONTAINS SPOILERS AND MOTION SICKNESS
I'm usually in two minds about Paul Greengrass films, and specifically his use of the hand-held wobblicam technique. While this technique does undeniably immerse you in the movie - you're right there, in the car or on the ground - it's advisable not to sit in the front three rows. This technique is actually one reason why I tend to like The Bourne Identity rather than the sequels Supremacy and Ultimatum: it's not going to inflict a dizzying headache on you. (It's also got Franka Potente in it, which is another plus.)
As with those two films, and United 93, you're quite definitely there in the thick of it in Green Zone, a film with a clear agenda against the WMD justifications for the Iraq invasion. That agenda suggests - and it does it very plausibly - that elements in the US government conjured up the spectre of weapons of mass destruction and then sent in the military to try and find them as a result of supposedly unarguable intelligence reports, except for the fact that the weapons weren't there, so the war could be seen as justifiable to the public. Matt Damon is the American officer tasked with investigating the supposed weapons sites, who's starting to query the reliabililty of the intel when he and his team keep coming up empty. He's not just up against Iraqi snipers and the like, but also those elements of the US embodied here by Greg Kinnear as a patently untrustworthy individual and Jason Isaacs as the more uncomfortably brutal end of the military spectrum.
It's a credit to the film editor that despite the shakycam sometimes making it difficult to keep your focus, you never lose track of what's going on; particularly in the hectic action sequences. They're accompanied by the usually reliable John Powell's score which in this instance is basically a background percussion riff and sadly not as enjoyable to listen to as his Bourne scores (or indeed most of his other work). Quite definitely a film worth seeing but don't sit too close.