As noted above "Right, because a universe set in Buffy isn't a Buffy game" - I guess you'll say Angel wasn't buffy because it involved adults and wasn't in a small town?
Pittsburgh, the City of Bridges as a "City of Bridges" (to other dimensions) is a wonderful idea. Its a city that mixes the ultra-modern high-tech with urban decay and absurdly old architecture. 400-year old coal mines underneath entire sections of the city, plenty of buildings (--plenty--) from the 18th century still very common - thats a decent idea.
But the thing that kills mushing is the extreme OCD; the 'I want to play the exact character with minor variations on every mush, in this ONE THEME, that I've done for XXX years and refuse to vary on'. Guess what? I'm sure Mexico has teens and young adults struggling with themselves, too! (And vampires!) Hell, I bet Dublin, Ireland, Johannesburgh, South Africa, and Paris... ....all have vampires! Its sad to watch the hobby decay from a writing pasttime into an OCD-outlet pasttime.
That being said, I think the Pittsburgh idea is a good one.