Back when I was a kid (well, teenager), I had an Atari 800XL and played a great many list of games on it. The one that hooked me most though is a rather obscure one: Alternate Reality (The City) and it’s sequel Alternate Reality (The Dungeon).
For me, that game was eye-opening. The game world felt really alive in a lot of tiny ways, and was in many more way ahead than other games. It used a raycasting engine, on 8‑Bit home computers nonetheless. It was basically an open-world game, where you didn’t wander through a set plot, but had to connect the dots yourself, and figure out who wanted what. That meant that you could suddenly die, because you wandered in the wrong part of the map, or that people you never met knew of you.
This thoroughly spoiled me for most of what followed. I couldn’t fathom why things had to be so static, why I couldn’t just rob this bank or plead with this monster. And the places made sense, even if they were labyrinthine. Also, with monsters like the „Clothes Horse“, it forged my sense of what is appropriate in a game and what isn’t.
Gosh, I miss that game :)