Yes! I remember finding out which integer was the money in my Sim City save. And I remember when I figured out the build order list for Star Trek: Armada 2 and fixed the Borg AI to be so formidable that we'd have to play the First Contact sound track at full blast to even have a chance of winning against 3 Borg players.
By later times it seems this was tougher, I remember trying it with Ultima IX and utterly failing to locate a single relevant memory location after a solid week.
Ya especially with DRM or multiplayer lockdown measures.
But there is still a revolution where most game files are JSON or plain text (like that build list from Star Trek Armada 2).
Dwarf Fortress is like this too, in fact much of the game can be modded from such files. I like that, but I do understand the frustrations of the developer who not only saw their games cracked but also trained back in the day. It presaged what was to come heh.