Gaffes

When the Army officer is giving his briefing in medium close up Sam Kydd can be seen to his left.In a longer shot Kydd has disappeared.

The Dark Man tries to escape using a boat left at the water's edge. No boat would ever be left there, let alone at night: twice a day it would stand to be carried away by the area's substantial tide.

The coastal castle featured is Camber Castle near Rye (East Sussex, UK), which is actually 3 km inland and far more distant (9 km) from the main area of coastal action (the western part of the Dungeness peninsula) than is indicated in the film.