The film features a recurring satanic theme, including many references to pentagrams
Gothic atmosphere throughout. Fog shrouded forests. Dark cobblestone streets. Graveyards, etc.
The Wolf Man attacks other characters with exciting music and lots of growling. Not overly violent by modern standards, but still thrilling, and potentially scary for younger audiences.
The Wolf Man is a tragedy, and depicts a man who is tormented by a monstrous affliction beyond his control. There is a melancholy quality to the character that may be affecting for some audiences.
The Wolfman may be frightening to some young children but the special effects and make-up aren't very realistic as the film was made in 1941, so children aged 5 or 6 and up probably won't be scared.