So how's the writing and loré
I didn't really bother with the Lore-pickups in Freeplay other than for their XP-value ... but aside from the Site-makers most of this stuff went straight into the Cortex (your enclopedia) anyway. Site markers give you a little pop-up window to read but you can just look it up in the Cortex later if you just want to get on (and I really wanted to get on, being in motion was felt best about the game after all)
Envoirmental story telling is a thing, but there is a lot context missing in the Demo; in the Freeplay area there was something like a Scar Settlement (including a Dungeon) but it is just there; Similarly near most spawn points there are small camp sites and structures that serve as indicator of the Enemies that might spawn; there are also neutral camps where you get your lore pick-ups but again context is lacking. And there are sometimes NPCs out there too, mostly for the World Events but also not e.g. there are always Sentinels outside the Fort's walls.
The whole world is dotted with what seems to be part of the large singular structure which I guess has implications for the lore but is not explained in the Demo.
As far as the in-mission stuff goes, you basically got 6 scenes with one character for missions, none of which is a proper introduction - he is just your "science guy" -, it got a little more interesting as by the second scene something interesting happens:
The artifact you were collecting does some reality bending and splits your science guy into 3 versions of himself (cause the artifact is called "Manifold"), each basically one of his main character traits made dominant. The rest of the questline is then to explain what happened and to prevent the trio from dying due to side effects.
It wraps up neatly as a sequence but is kinda "there" in term of an overall narrative that is supposed to be happening; there is no explaination why we are fighting the Dominion in one mission other then "they got the codes we want" or the Scar in the next other than "they kidnapped the people we are looking for".
The Stronghold (think a Destiny-Strike) was actually a bit more lively and explained itself somewhat through the banter of your three mission handlers (Regular Handler, Guide Handler, Mission Giver Handler) and your Freelancer; some it was quite humanistic, e.g. a running thread that the Mission Giver Handler is disgusted/has a phobia related the insectoid Scorpion-enemies, which make up the opposition during the second half of the Stronghold.
The best indication for World Building was actually chatting up the NPCs is Fort Tharsis, but that felt rather inconsequential - esspecially since it basically sitting there listening and at one point during the dialogue making a binary agree-disagree choice, which doesn't seem to change anything but what lines come next.
However the dialogue writing is actually quite humanistic ... despite the NPCs avalible being rather architypical; e.g. there is conversation with your Mechanic you can have about how all the other Lancers (=Javilin Pilots) doesn't appricate the comfort features she can and will install into the Javelins (its all rather mischiefious, instead the usual "complaint about roughing it"). They seem to have put some effort into the in-universe perspectives instead of just sanding down the archetypes until they fit, at least in what was on offer. It's not helped by the animations that are supposed to give each a distinct mannerism not being quite there-there - the clash between the mostly-realistic style and the technical flaws is bit too obvious (Maybe I am just fishing for another "See that why you don't go with Realism as a style"-argument).