Very nice quiz but you could add more cities to the map! Several enormous brazilian cities are missing, such as Belo Horizonte, Manaus, Porto Alegre, Recife and some capitals such as Montevideo and Assuncion.
Surprised to see Port Stanley here and suspect Jiaozira may be having a little political fun with us. Although geographically close, and part of the South American plate, PS is a British Overseas Territory and certainly not South American.
By the same token, the quiz might as well have included cities in Trinidad or Barbados which are much closer to South America than the Falkland Islands.
The UK is not a South American country. But Stanley is a South American city. Similarly, Greenland is owned by Denmark, but it's part of North America.
Puerto Argentino should be accepted. At the very least to honor actual geography. Forget what a senseless war determined. Malvinas are part of the South American Plate. Otherwise nice quiz!
São Luis seems like an odd inclusion (and I'm not just saying that because it was the only one I missed). Most of the others seem to be capitals (Brasilia, Santiago, Buenos Aires), amongst the largest cities in their country (Barranquilla, Sao Paulo) or geographically distinctive (Ushuaia, Port Stanley). São Luis seems like the only city that doesn't fit in this. Brazil's capital is already covered, but there were much larger cities that were excluded (Belo Horizonte or Porto Alegre, for example) and Manaus could have been included (both a larger city, and in a more geographically interesting location).
São Luis is certainly an unusual inclusion on my part, however, especially after looking at the answer statistics, it serves a good spot in making the quiz tricky. I will say that had I made the quiz today, with all the Brazilian cities I've encountered on Jetpunk in the last four years, I probably would have gone with Manaus instead.
By the same token, the quiz might as well have included cities in Trinidad or Barbados which are much closer to South America than the Falkland Islands.
Geography is fun and confusing. Hooray!