Just finished watching this version of Agatha Christie's marvelous tale. Rene Clair seems to film it like the stage play it originally was, as every so often, he has the characters looking directly into the camera as they speak. Not just a close-up, but directly into the camera.
This is my favorite of Louis Hayward's performances. Of course, Walter Huston and Barry Fitzgerald are always a treat to watch. What thoughts does anyone else have to add?