Nothing short of a masterpiece. If Citizen Kane never came out, this film would be the standard. Everything from the title sequence to the close up of John (Jimmy Stewart) at the courthouse where his head compositionally is in a red square like a boiling pot surrounded by blue. The latter example is subtle but Hitchcock is known to have everything done down to the tiniest detail, and that was no doubt on purpose. Hitchcock's sometimes gimmicky camera effects now are used perfectly and at only the biggest moments.
Even the plot is complex and full of intrigue: a man falls in love with a possessed woman. Then of course the twist: the possessed woman turns out to be an actor portrayal, but has also fallen in love with the man. I remember when I first saw the movie it was during a series of classics I was going through and I had been writing notes in a little notebook and then rating the movie out of ten. From the second half of the film to the very end, I kept writing "omg, omg!" with ever increasing emphasis until the credits. I had no different a reaction this time. The genius of the story is by the fourth quarter of the movie, I too had vertigo—all the plot twists, all the complicated story archs, and all how Hitchcock made it work so perfectly.
Even Midge Wood's (Barbara Bel Giddes) arch was fleshed out and complicated. She ends up thinking John made up the whole thing to have an affair (even though their relationship is pretty open, but push comes to shove like any good story). She ends up thinking she's right, but she's also wrong. There was in fact a job he was doing, but he happened to fall in love with Madeleine (Kim Novak).
Then of course the complicated relationship between John and Madeleine, who is back to living her old life, torn between trying to get rid of John, her feelings for him, and not wanting to tell him the truth. Then John— torn between his trauma, wanting to be with Judy because it reminds him of Madeleine, not knowing that they're the same person and he's not going crazy. She can't tell if she loves him for her or for Madeleine, and he struggles to figure out why they are so similar. That scene where we find out it was an act and then she writes a letter of confession but then rips it up! It's an emotional roller coaster ride that somehow manages to up the ante every minute. Then finally, once John gets what he wants, he catches on to the act.
It will really take multiple consecutive viewings of this and slowly treading through each scene to get the full understanding of the craft of this masterpiece, but as of right now I'll stick to this short post and wrap it up with an emotion: oh my god.