The appearance of the mysterious titular character is rather eerie and foreboding, and may upset or frighten sensitive viewers. Some of his appearances are abrupt and unsubtle, usually accompanied by a 'sting' sound effect which can be startling.
The film overall has a foreboding feel to it, and the Victorian setting with gloomy mansions and steam engines can make it seem all the more unsettling (reminiscent of the British ghost story adaptations). There are some more intense than usual moments compared to other CFF films of the era, but there are occasional light moments (as well as a twist ending) which should alleviate the apprehension of sensitive viewers, but may still make for unsettled bedtimes.