Le trou is little over two hours, has no music and little dialogue. The actors are all amateurs, some even prisoners, and most of the film takes place in a cell shared by five men. There are just two scenes outside of the prison. But the tension and the atmosphere are remarkable. It's almost a zenlike experience to watch it. The quiet desperation of it all. It's a beautiful film.
I haven't seen enough of Becker's films to talk about his work with nothing more than generalizations, but of those I've seen Le trou is by far the best. And now I want to see Casque d'or (1952) again.
(All the films I've mentioned are available on dvd.)