Ah, the bitter pangs of disappointment. I'd planned to see this during its theatrical run because it was advertised as a politically engaged "grown-up" thriller as well as adapted from a Le Carre novel. Not that anything claimed as grown-up or adult means anything other than self-congratulation on people making the claim but I'd hoped at least for more complexity than usual. But this is no more grown-up than any other Hollywood outing, the politics are decidedly regressive and it's no more complex than any TV cop show.
A main problem is that the real focus of the film should be Justin (Ralph Fiennes) as he progresses from a routine diplomatic politics to something more involved and layered. Instead almost the entire first third of the film is devoted to flashbacks of Tessa (Rachel Weisz), a character who could barely be called two-dimensional. Tessa is only a catalyst for Justin and nothing is fleshed out (except the softcore porn at the opening) beyond her purely plot function. (Inexplicably Weisz won an Oscar for this but then again maybe the unthinking safety of the character is the reason why.) I'm curious how the novel is structured and may even read it someday but in the film by the time we get to Justin's reaction there's no momentum.
Even more surprising is that in 2005 somebody could make a film that has such a near-racist colonial view of Africa. Sure they're careful enough to be clear that this is Kenya and not some abstract "Africa" but that hardly matters. Kenya is presented as postcard pretty when it's not slum-ridden and the resident Africans are pure stereotypes, most of them not even given names. Noble savages, savage savages and the quietly suffering. This could easily have come from 1955 or 1935 or even 1855. Combine with a cliched knee-jerk anti-big business theme (however true this might be in reality) and the film would come across as distasteful if it wasn't so deadly dull.