Enjoyable, involving, suspenseful, unpredictable. Hitchcock is hitting his stride here. The only quibble is the somewhat incongruously light tone compared to the grim subject matter. This might have something to do with Robert Benchley being one of the screenwriters (and actors). As usual for the time, Hitchcock preferred to shoot indoors for outdoors and the sets have a wonderful hyper-real effect, especially the interior of the windmill. The Escheresque quality of its crisscrossing stairways is fascinating (even though this preceded Escher’s most famous works). Very much worth a look.