Frontier: Elite II (1993)

The sequel to Elite had an ambitious goal: to simulate the entire, real-world Milky Way galaxy. Including the ability to land on millions of procedurally generated planets. While still fitting on a single floppy disk.

In the original Elite, each system had exactly one star, one planet, and one space station, and the variation in the procedural generation was focused on the economy and the system’s position in relation to other systems. Frontier: Elite II tries to simulate as much of then-known astrophysics as possible, with binary star systems, exoplanets, and so on (but, alas, no black holes).

It also included many real-world stars, with procedurally generated planets and realistic distances. This made Proxima Centauri something of a pain to get to, since it is 0.23 or so lightyears from Alpha Centauri A and B.

The sector-based procedural generation system did have its limits, including some repeating sectors due to flaws in the way galactic density is hashed into the generator. The galaxy is also mostly treated as flat with stars that rise above and below the plane, which messes with the positioning of real-world stars. 

Still, the intended limits of the travelling range mean that most of the flaws weren’t discovered until years later. That they were discovered at all is more a testament to the dedication of the playerbase to a game they couldn’t quite find a replacement for.

(Because I can’t find my copy at the moment, the video is via https://www.youtube.com/watch?v=XP0Wfn9_nnc and courtesy of CuteFloor.wordpress.com who have a ton of videos archiving videogaming history.)