We're all so used to modern abstractions, libraries, data-driven engines, general solutions. We can afford them now. The developers of these old games couldn't, they were forced to do more with less. The results are absolutely fascinating. There's a certain quality that seems to have been lost over time as computing resources available to developers have improved.

It would be surprising if those old game developers didn't have their own library of code, gradually perfected from game to game. That would have been their modern frameworks.

The procedurally generated universe in Elite [1] contained 8 galaxies and each galaxy had 256 planets. They were all generated from a single seed number.

Interestingly, they artificially limited the number of galaxies as theoretically they could have 2^48 of them.

[1] https://en.wikipedia.org/wiki/Elite_(video_game)