To follow up on agumonkey's additions, to me at the time, all the elements combined to give a sense of presence (in the VR sense) that I'd never really felt in a game.
Characters talking to you in-game, banal everyday moments and a believable world (ex elements caused by "the accident"), seeing your hands, a reactive environment (remember, for you youngsters, boxes shattering and random items on desks being movable was novel!).
All the little details added up to just make the world feel different than other games I'd played.
Yet that's what all the reviews are about. Resolution centerfolds. And I get that, I was much into this as a teen, software stack and video cards that would allow for shinier. But it doesn't really last, especially when people spend too much efforts justifying a new game on this rather than making an actual game that is funny, surprising or inspiring.
Characters talking to you in-game, banal everyday moments and a believable world (ex elements caused by "the accident"), seeing your hands, a reactive environment (remember, for you youngsters, boxes shattering and random items on desks being movable was novel!).
All the little details added up to just make the world feel different than other games I'd played.