Fuck yes. I finally get to rant about how good Deep Red is because I need to.
David Hemmings as the main character was one of the best choices for the film as he's such a believable character who's gotten way too deep into shit for his own good but he has to keep pressing on to survive.
Daria Nicolodi is such a good foil for David too, she's very good as the romantic interest who takes no shit from David being kind of misogynistic at the beginning.
The mystery is one of the best in any movie ever and the twists and turns it takes leaves so many red herrings and gets you guessing gaaaah I love it.
The death scenes are fucking phenomenal too, so is Goblin's score of the film, and the cinematography is arguably Argento's greatest from a film perspective.
Of all Argento's films, between this and Suspiria, I'll always say this is his best film ever.