A fairly decent adaptation of the Lovecraft story of the same name, this film is more true to the original story than most other H.P. Lovecraft inspired films.
Dean Stockwell is totally believable as the strange young Wilbur Whateley who's family has a history of being just a bit odd. The rest of the cast is decent, even female lead Sandra Dee is tolerable.
The only thing that some viewers may find distracting is the fashion in this film. The film was made in 1970, and it REALLY shows - in the quality of the film stock, and also in the hair styles of the characters (Dean Stockwell's perm is absolutely awful) as well as their dress (remember those bell bottom pants?).
If you like Lovecraft, you'll like this film. You don't get to see many of his stories kept nearly intact once they reach the screen, but this is certainly one of them. Sure there are differences in the story and the screenplay, but all in all an enjoyable film for Lovecraft fans.