Amazing game and an incredible technical achievement.
Still confused about the "procedural stuff". Are the missions infinite and randomly generated and that is the whole gist? Or does it have a central story, a start and a finish?
It procedurally generates a city based on your preference (size, etc), then procedurally generates citizens for that city. They all have jobs they go to, friends and family they know and visit, they all live in a house, etc. There are a million possible connections between them via phone books, address books, emails, working at the same place, visiting the same pub, it's insane.
And then crimes happen that you need to solve by finding clues. Because everything is procedurally generated, you're never playing the same thing twice.
So let's say you're in your apartment and you get a mysterious note under the door to go to a specific address. When you get there you find a dead body. You don't have a lot of time because the cops are on their way. You look for clues, read mails, browse through the address book, check the calender. Take finger prints, the whole thing. And then you start piecing things together, like "o this person died 3 hours ago, according to the calendar they went for a drink with person X at this and that café. Let's go there and steal some security footage to see what's up", o shit the cops are at the door so you quickly escape through the air duct but o fuck now you're in someone else's apartment so you have to sneak out etc. etc.
It has a level of depth I have never seen and it is quite overwhelming how many ways there are to gather information. And everything has this noir vibe with rainy streets, neon signs, synth music.
My suggestion is to watch a lengthy gameplay video because a 90 second trailer cannot possibly do this game justice.