How long is a colossal game? Well, it takes 60+ hours of continuous playtime to finish Disco Elysium if you're a reasonably completionist player, as I am. It takes 90 hours if you're absolutely savouring every detail. And 30 hours if you're rushing it. Back-of-the-box, I would put playtime at: 60+ hours.
The world is about the size of Planescape: Torment. Or a sizeable chunk of the first Pillars. A sizeable chunk of Fallout: New Vegas... But the resolution – the level of detail, content density – of these areas is, I would say, about 5 times denser than any RPG I've played. Disco Elysium is a detective game and thus you have to be able to put it under a magnifying glass. Any part of it. Every apartment, hallway, street corner, lamp, or even trashcan needs story, writing, details and interactivity that, to me, exceeds even the most detail-oriented adventure games.
None of these areas reuse assets or look the same like games that are asset-assembled do. Sure, people have the same radio every now and then, every little room is 100% unique when it comes to layout and art. And music, too.
Disco Elysium has about 100 "quests" – or whatever you call them. We call them "tasks". Tasks range from minor to-do's a la "have a bath" to side-adventures that take a whole day to complete. We don't differentiate between side-quests and main quests, by the way. It's all one big thing -- the story of your life in another world, as a detective of the Revachol Citizen's Militia.
It is one million words long.
There are 70 characters, all have partial VO. Each you can spend hours talking to, each has hours of secret content.
Aaaaaand you're gonna have to play the thing from beginning to end three times to get to see most of it. To see all of it... I don't think a single human being can. But the internet has proven many a boast wrong, so let's see.
It's honestly inconceivable how we managed to do this. I guess time is the answer. Disco Elysium took 5 years to produce. We only managed to make it so fast because we had a head start with worldbuilding. A whopping 13 years worth of D&D style pen and paper games in the Elysium setting beforehand.