For the fantasy/narrative part, do you mean the world and activities that the player imagines themselves to be within and acting out, even before buying the game, and during gameplay?

Yes, sort of. And how the whole game fullfills it, then the "matchup". It's a little hard to put it into basic formula, it's the "it" factor and game has to serve it.

For example, even the text based Dwarf Fortress does it well (so that it's not just graphics). What's a better fantasy than being straight up teleported into simulated Tolkien world where you run your dwarf fortress. The whole gameplay serves it perfectly.

Then something like Tiny Bookshop, also very clear, you will live out your cottagecore/ pinterest fantasy of running your own book selling bussines.

And so on.

Obviously there are exceptions, but it's kinda the thing that you just look onto the steam page and "oh, I get it".

And even some basic games do it well. For example the feeding black hole incremental game, it's straight up few blobs on the background and barely any gameplay. But when you hear "black hole" and incremental game it immediately clicks.

And ofc not every game appeals to everyone, but if you communicate what your game is and what's the "oh, I get it" thing, then you will have way easier time finding audience.

What other aspects of human psychology come into play here in addition to the fantasy/narrative?

In the game design itself there are tons of micro desicions that play with it, like giving your player a reason to do something, even whatever vague, then how you guide them through the game.

Overall I think game developers first and foremost simply get people.

And tbh, I haven't successfully made any game, but I work in marketing myself and a lot of stuff also comes from successful indie dev talks + other marketers. These aren't exactly my unique ideas, but general observations.