[quote=@Helo]
[@Ruby] so would it be like the events of the show never happened or somehow the world has gone back to only one slayer at a time? Is there a town shaped hole in the middle of California?
[/quote]

Not never happened, but at a certain point the timeline was "corrected" by a Supreme Being; no Buffy, no Gang, no Hellmouth under Sunnydale. The storyline to this game deals directly with the consequences of that act by that Supreme Being. Buffy, Angel, Spike, etc, may be referenced, but more like legends from a lost, last, age than actual people from an actual fixed point in history.