Melodramatic and crazy. These are the two words I would use to describe Nightmare, the story of poor Janet who is haunted by persistent nightmares of her mother. Jennie Linden plays the troubled teen in question. There is no doubt she brings a LOT of energy to the role. However, I would argue her performance is a bit over the top for me. Crazy is always more interesting when it's subtle. [Anthony Perkins in Psycho comes to mind.] Trust me, her performance is far from subtle. The same goes for most of the other women in the cast as well. It's a bit too much for me but others might find it quite entertaining.
The strongest elements Nightmare has going for it are its cinematography and direction. It is a well made black and white film with beautiful use of light and shadow. Director Freddie Francis [The Elephant Man, Cape Fear] definitely knows how to deliver the good in terms of the pacing of the story and the overall look of the film. Furthermore, the Netflix version of it I streamed on my TV looked very good. The picture was crisp and clear and the sound was good as well.
The only negative thing I have to say, other than the way-over-the-top acting, is that the script needed a bit more work. It starts out strong but then looses steam toward the end of the film. With a little more work, Nightmare could have been a really great film. It just doesn't quite reach that spot for me. If you like psychological thrillers you will probably enjoy this one.
For more info check out the film's entry in IMDB.