I used to play this on the Playstation in my teens together with a friend. On nights when I stayed over at his house, we played D all night. It was exciting, but also scary. We didn't want his parents to know we were playing D when we were supposed to be asleep. We'd take turns: He'd put it in and play for a while, then we'd switch and I'd do the same. There was a 2 hour timer, which meant that even though we wanted to just continue playing forever, we'd have to finish before that. That said, we never did finish. And you need to switch twice after the first time you insert it, but we always just switched once. But then we'd just do it all over again the next night. That's my memory of D. I've also always liked the cover art, with the big D and the girl, presumably Laura, with some liquid running down her face.
(All of this is true. However, how you interpret it is up to you.)