Buried is, more literally than most times the term is used, an exercise in constrained film making. In this respect, parallels can be made to the Hitchcock classics Lifeboat and Rope. More generally the film is Hitchcockian inasmuch as it places an everyman character in a terrifying what-if situation. The build up of emotion in the film is intense. While there may have been too many plot twists for what could be expected from an hour and a half in a box, the scripting was quite remarkable for being able to remain interesting in such a setting.
The film has two main strengths. Firstly, the direction, cinematography, and set design were all perfect; each was surely a triumph of film making prowess. Buried is a movie that people will be watching in 50 years to talk about the technique with which it was made. The second great strength of the film is Reynolds' performance. He almost single-handedly carries the film. It's no small feat, as he is the only actor with on-screen time for the whole 90 minutes.
Where Hitchcock generally used his films to probe the quirks of the human psyche, Rodrigo Cortés uses the last act of the film to explore morality. In the end, it doesn't matter whether or not the protagonist escapes, but what got him in there. It's an interesting and valuable life lesson.