If this was based on an actual novel, as the credits claim, it has to be filmdom's sorriest screen adaptation. (Then again, the book angle could have been fabricated by crudmeister Jerry Warren, whose cinematic transgressions include bogus credits.) Like MONSTER A GO GO ('65), this plays like an unfinished film. You pity old hands Tom Drake and Andrea King, clueless that they'll "star" in what amounts to a series of barely connected scenes.
On the other hand, Lon Chaney and John Carradine probably knew exactly what type of muck they were standing in. Carradine hams his role of family patriarch so badly, Hormel could sue for product defamation. Chaney, possibly hired because the plot includes a werewolf, plays a horned satanist who limps with an (unseen) cloven hoof...or did he just drop a hooch bottle on his foot? Familiar TV face Jerome Thor is screendom's most pitiful lycanthrope, though he gives it what I guess is his best shot.
Master film mangler Jerry Warren attempted to finish the film by randomly inserting new scenes that add nothing but running time. Sparse music cues contribute to the lethargy.