Andy played by different actor in the opening scene!
Interesting piece of trivia. I just watched this film for the first time ever last night, and didn't even realize that Richard Backus did not appear in the opening scene. As described at this link, the opening scene was added later, and they had to sign on a different actor to play the role:
http://www.horror-wood.com/deathdream.htm
--Daniel W. Kelly, author, "Closet Monsters: Zombied Out and Tales of Gothrotica"