It's a truly creepy, odd, ultimately mean-spirited film which makes brilliant use of Walken as the vehicle for Pinter's omnipresent sense of dripping menace lurking beneath a patina of polite words. Walken, who is menacing while being amiable and polite, even while being gracious, was born to act with Pinter's dialogue. There could be no better setting for these sinister goings-on than Venetian alleys and interiors. This is probably the most fully realized example of Harold Pinter's genius on film.
