Points for the bold gross-outs, but everyone except Christopher Lee seems bored (the blasé reaction to a woman being stabbed to death...case in point). The red demon muppet...which looks like a member of the Lollipop Guild from The Wizard of Oz, covered in cranberry sauce...easily steals the show.
The last Hammer horror film is unfortunately not one of their best, an uneven adaptation of a pretty mediocre Dennis Wheatley novel. Christopher Lee and Denholm Elliott give it their all, as usual, though Richard Widmark is a bit past his prime, and Nastassja Kinski is nothing special in her film debut. It has its moments, but it's slow-paced and fairly forgettable.