Continuity mistake: Just before the giant tarantula attacks the house where heroine Mara Corday is studying, you can see several book on the library table at the big picture window. The largest book on the table keeps shifting positions in several scenes.
Continuity mistake: Lobo has a very distinct scar on his cheek in the beginning and end of the movie. However, just after Dr. Strowski has entered the house, Lobo is seen coming down the stairs, and his scar is completely gone.
Continuity mistake: When the bogus male nurse with Mrs. Carroon is outside in the rain, his coat and hair are soaking wet. But when they run to the staff entrance (a few seconds later), his hair and coat are bone dry.