The city falls without it being entirely evacuated, thousands die (Tony makes the choice), quicksilver dies trying to fight ultron one on one in the aftermath (damn it was dumb how he died). The clones are wiped out, main ultron is destroyed by vision but says something about one down ... to go. Vision has a slightly puzzled look but doesn't share this information with the others.
Boom Ultron at least partially delivers on his threat, massive consequences for civil war and Ultron is still out there in the minds of the audience.