Now this is not just about the first Psycho - but kind of neglects the Bates Motel movie - and that is not really a bad thing, because the less that is said about that, the better. Especially because it leaves time to talk about the "real" movies. The ones with Anthony Perkins in them. And just in case you didn't know: The documentary you are about to watch (if you are reading this to make up your mind), will spoil the Psycho movies.
So the big spoiler in the first Psycho is revealed. The McGuffin of casting and of course of the poster and really something very ingenious, that I didn't want to talk about in my review of Psycho itself. Here are quite a few directors that were directly influenced by Hitch and Psycho itself. And it is a great movie - and one of the first that was very strict on the no spoilers rule. Now they also had a no one is admitted after the movie started rule - not sure if they upheld it everywhere but it makes for a good story and something the interviewees seem to remember fondly.
Now since Psycho 2-4 are also discussed, you will get some interesting ideas. And also interestingly enough some riffs. So the makers of that sequel didn't like that sequel. Which might explain why a few things didn't really make sense time line wise. Only Halloween has been more all over the place when it comes to different versions (or realities/alternate timelines). It's really a powerful documentary and if you are a fan, there are still some nuggets you will find here