One thing I find really impressive about this game is that it contains genuine exploration of a vitual world.
When the devlopers say you arrive at a planet and your the first person to discover it, you really the absolute
first person, ever.
The planets and their characteristics are defined by the methematical algorithms, but Hello Games will not have rendered every single one of the 18 quintillion planets during development. Most of the planets in the game will exist purely as their mathematic blueprint, they will never have been 3D rendered.
So when you first arrive at a planet and your PC renders the mathematics into a world and displays that to you as a user, storing the 3D render of it as bits and bytes in your PCs memory and on disk, that is quite litterally the first time that will have happend, ever.
Hello Games haven't built a universe which we will then go and fly around. They have built the instructions for a universe, and us as players will then set about building it.
The technology behind this game impresses me regardless of whether the game is any good. They have built a universe that would take a single person billions of years to fully explore and render, and it all exists in 6GBs of code! I can drive from one side of the GTA5 map to the other in a few minutes, and that games 50GB+!