Starflight on Sega Genesis. Starflight was a formative game for me. It’s an open world space exploration game with ~800 planets in over 200 solar systems. And it pretty much just drops you in the middle of it without any explanation. After a bit you get some news updates from your home base talking about a huge, imminent threat that’s destroying entire solar systems, but they don’t hold your hand, and the galaxy is massive, and it’s impractical to find the points of interest in such a large space. I watched my dad play it as a kid. We spent hours exploring and gathering resources up upgrade the ship and explore further, but we never really scratched the surface of the main quest. Then as a teenager I went back and finally read the fucking manual. The back half of it was a journal written by a space captain not unlike myself, which had been sent back in time from several months in the future. It gives tips, like how to communicate with the different alien species and the locations of some rare items. More importantly, it guides the player to the main quest, which is fucking amazing. All of this written like a captain’s log, so it’s a fun story in its own right. Starflight manual: expand   Second answer: Tunic. This one is cheating because the game is about nostalgia for manuals, but it’s so well done. You find these beautifully illustrated manual pages throughout the game, and they become an essential part of figuring out the world. Part of it is written in a made up language, and every page you find gives you more context to translate it. Then there are abilities you have from the moment you start the game, but you won’t realize how to use them until the manual gives you simple button instructions. Amazing game. If you love old school game manuals, you need to check it out. They later released a version with a physical manual, but you shouldn’t look at the pages until you find them in the game. Tunic manual: expand