 The DVD version released as "Astral Factor" is a rather different movie from  the DVD released as "The Invisible Strangler." The killer is not only seen  throughout in "Astral," but talks frequently (as opposed to never in  "Invisible Strangler," where he is also invisible after the first scene up  until the end) Most of the scenes he is in, including the opening where he  first becomes invisible, is completely reshot with a different cast, features  different music (as does much else of the movie), has different action, and  often strikes a different tone. "Astral Factor" also fills in many missing  plot points from "Invisible Strangler" with the inclusion of material edited  out from the other version, which are usually easy to spot by grease pencil  marks on what is obviously a work print. The running time is about ten  minutes longer for "Astral," despite the fact that the opening scene, in its  completely different version, runs about that much shorter than the one in  "Invisible."