Really Awful
I mean, it is fun to watch Oliver Reed and Donald Pleasence in thoroughly embarrassing roles amid a mix of interesting and laughable sets and set dressing... And I was actually laughing by the "grand finale". But this is a mess, functioning only as so-bad-it's-good comedy.
Naturally, it bears only the most minor and superficial similarities to the Poe story, but that is typical of most Poe adaptations and is the least awful thing about this utter shit show.