When I was younger I took a few screenwriting classes and we had to watch this in each of them, because it teaches writers that you can make an amazing film with only one location.
If you're interested in the long take / sequence shot, it goes from about 2:22 to 9:40.
At 2:22, the jury stands and exits, and we see the accused as it dissolves into the jury room. This starts the long take / sequence shot.