As Ebert said, this is a film that says "WMD don't exist" and (as he and my friends said) "people are dupes corruptly hiding the truth." Watching this film in 2010, one does not expect a positive outcome of this situation. Yet Greengrass gets us behind Miller, who, as someone I know said as well as the DVD case as well as friends, "is on a search for the truth" and who is trying to get to the bottom of whether or not the WMD are there. But the soldiers of his own side keep getting in his way, as well as Clark Poundstone (Greg Kinnear), who wants Miller shut down. Poundstone is also the guy who mediated between journalist Lawrie Dayne (Amy Ryan) and "Magellan," who's a "source" and who supplied information about WMD and where they were hidden. Problem: Miller has already been to some of these places, and no WMD abound.
Perhaps the film's key character is Freddy (Khalid Abdalla), who, while Miller is basically wasting his time going to locations that are already bound to have nothing within them, tips him off about an important gathering at some house. He also acts as an interpreter for Miller. He really gives Miller a lead, and changes the game later on in an ironic way.
The film has an ending that fulfills our fantasy yet at the moment of its arrival seems (although there is another, somewhat embarrassing reason for how I felt this way) abrupt and too good to be true. It's both a good thing but also a flaw. That and also the very long follow climactic scene, which can be admired for its "chaos" (as my friend said) but not for its clarity (which may in fact be the whole point, but still). I did think Damon, Kinnear, Ryan, and Gleeson all did pretty well, fitting appropriately in their parts, although Damon is a little typically "heroic" (as has been said) and Gleeson is in spots a little weak. "Green Zone" isn't all great, and the only areas where it really excels is in its (as other critics et al. said) "technicalities" and (as others said) "feeling," but it's a solid film, on par with Ridley Scott's "Body of Lies." B