Earlier quoted context omitted.
[spoilers] 999 relies on the two screens for the actual purposes of constructing the narrative(s), as well as for the big reveal at the end. The story is unfortunately a layer shallower on the PC port of the game (not to mention that you have to choose between one of two options for dialogue, neither of which is all inclusive).
> 999 relies on the two screens for the actual purposes of constructing the narrative(s), as well as for the big reveal at the end What does it do with two screens that couldn’t be done with one screen divided into two halves?
There's also the part near the end where you play as Akane directly, and you play with the DS turned upside down in your hands, but that's more minor versus the fact that the entire game actually takes place on a meta level.