The visual effects sequences featuring the Japanese ghosts were filmed utilizing an old German camera technique known as "Shauftausen". In a 2011 interview with John Kenneth Muir, director Kevin Connor said of this: "...basically you shoot the scene with one camera through a right-angled mirror. The ghost actors are on a black velvet background so you can control the density of their image as you shoot, ie you fade them in and fade them out and line them up easily with the 'live' actors. It worked very well, and of course you could see the composite dailies next day. Eventually we got this technique down to a fine art. It was important to show the ghosts in this fashion because basically it was an economical and effective process".
This is not one of Kevin Connor's favorites of the movies that he has directed. He said that this is because the film's producers re-cut his version after he had submitted it, with the depth of the relationships between the characters being lost.
The scary giant spider crabs sequence took about half a day to shoot.
Director Kevin Connor has said of the film's major love scene in a 2011 interview with John Kenneth Muir: "The interesting story about this is that the producers wanted a more graphic sex scene, which wasn't in the script. So Edward Albert and Susan George agreed to do it on their terms which was that Susan would wear her panties because of an experience she had had on Straw Dogs (1971) where somebody at the lab [allegedly] had copied some of the revealing out-takes from her nude scenes - so she certainly wasn't going to let that happen again. You can imagine how difficult it was to shoot a nude scene with both your leads wearing underwear, but it worked out very well".