Buried takes place in a wooden coffin. We never leave the coffin. No cutaways to the world outside. Our protagonist (Ryan Reynolds) is an American truck driver who has been kidnapped and buried for reasons best explained by the movie. Everything we see is seen by him from his coffin prison.
Director Rodrigo Cortes pulls it off. Yes, he keeps things tense and visually imaginative. A visually imaginative coffin film? You bet. Shocking, I know. But his approach is to depict the coffin as a world unto itself in which the threat lives within, above, and occasionally slithers in from below. There's no lack of jeopardy here, and that's why the film works so well.
Reynolds has a cell phone, a flashlight, and a lighter. Each of these provide their own color scheme and a window to the world outside. The other actors are only heard, and we get snatches of Reynolds' past and present through his frustrated interaction with them.
The film is set in a familiar war zone, and this fact adds more drama to an already dramatic situation.
I appreciate films that work hard to make the most of either an enclosed location or a (potentially) visually dull location. One example of the latter that springs to mind is Oliver Stone's brilliant Talk Radio.
That did visual and aural miracles with its radio station setting.
Buried performs a few miracles, too. Give it a shot.