Thanks. It does look like it depends on special buildings, but 800+ is definitely a bit of gaming the system. Still pretty cool.
I posted a full log of a 450-point game that used no special buildings. After that, I scored 489, with the full log posted here. Using that as a guide, breaking 500 should be possible even without the Zoo (I think the Business Park is a net 12 points or so by itself, for instance).