Of what i've seen and read of this film, specifically the documentary images in 'the making of Hitchcock; Helen Mirren BADLY plays a witty shrew, which Alma most definitely WASN'T, she was a quiet dowdy little old lady, who looked real old btw at the time of Psycho, and not ANYONE who ANYONE would want to have an affair with, which is a TERRIBLE bit of fiction that makes her character COMPLETELY different from what it really was.
And Anthony Hopkins plays a fat mean version of an Anthony Hopkins stock character, NOT HITCHCOCK, in any shape or form, except maybe the fat gut, which in Hopkins' hands is as exaggerated as the inventions HE comes up with to pretend to be quieter, wittier Alfred Hitchcock.. These two stars act like they never saw an inch of film of their characters' mannerisms, nor tried to play them as they were, which was actually much more interesting than the tabloid types they look like in this film. Helen Mirren's protrayal is the worse of the two, giving life to a character that bore NO RESEMBLANCE to Alma's actual personality, despite Mirren's claims to the contrary. She does Alma a deep disservice.