Just a note--as should be covered in the thread to which Midnite posted that helpful link, Darkness at Blaisedon was not a feature film; it was a pilot for a nighttime series co-starring the legendary Kerwin Matthews and Marj Dusay (who had guest roles on Star Trek, the Wild Wild West, and other shows of the period we all watched). Cal Bellini was in it in a very Aristide-like role.
Blaisedon was done on videotape, written by Sam Hall, used all the classic DS music cues we love by Robert Cobert, and had a supporting role for Thayer David and what amounted to a cameo for Louis Edmonds. I think it runs around 50 minutes. It's a fun thing to see, but if you expect a glossy feature film with lots of explicit gore and violence like hoDS and NoDS, you'll be disappointed.
The best sources for the movies *currently* are, IMO, the laserdisc releases. My own videotapes come from those discs which I own (a friend made the tapes for me since I never owned a disc player). According to THE authority on the movies, Mr. Darren Gross, the sound mix for the recent broadcasts of NoDS is superior to any version ever released on home formats (at least, that is how I understood a remark he made about this a year or two ago), so your disc may be an improvement upon the laserdisc version in that respect.
At least the laserdisc does not have any annoying logo... or commercial breaks!
cheers, G.