The movie was dubbed into English, French, and German versions for different markets. Its actors came from varied national and linguistic backgrounds, and so in certain versions it appears that some of them are speaking their lines phonetically. Additionally, the film was shot fairly cheaply using an experimental sound process, and the technical quality of the soundtrack leaves much to be desired. Most versions in distribution through the late 1990s (including those on video) are composites of the German and French versions, which differ for cuts made by the censors in each of those countries. As of 2004, no prints of the English version are known to circulate.
In order to achieve the strange, dream-like photography, A thin gauze was put in front of the lens as a filter.
The film was shot entirely on location. In fact, the old castle featured in the film also served as the lodging for the cast and crew.
The dank doctor's surgery and its abandoned, dirty look covered in cobwebs was said to be achieved by the director breaking jam jars on the floor then leaving the room shut off for a little over a month to attract various bugs and insects.