This is an excellent horror movie.To be buried alive is a fear we all share ,and although it's not really new (outside Poe's obsession there's a sequence in Dreyer's "Vampyr") ,it's terribly effective.
Ray Milland portrays a man whose obsession knows no bound.His mausoleum which he shows to a distraught wife and to his good sensible friend and the nightmare are worth the price of admission.The foggy ghastly atmosphere -pure English sixties studios - adds to the almost unbearable suspense.The screenplay,which,like all the other Corman's adaptations ,is rather far from Poe's short novel,is full of good ideas (the undertakers whistling a gentle tune when they open a grave,the cat,the unexpected final twist which is quite successful).
"Premature Burial" is to be recommended to horror movies buffs.
The fear of being buried alive never came to an end ;two examples "Oxygen" featuring Adrian Brody and "Spoorlos" (aka "L'Homme Qui Voulait Savoir")