I should explain, ha ha. Most of the countries I used to mix up seem to run west to east or north to south in alphabetical order. It works for many confusable countries, like Estonia, Latvia, and Lithuania or Guatemala, Honduras, and Nicaragua.
The 2 Congos, the 3 Guineas (not counting PNG), Slovenia & Slovakia, the 3 "Saints" in the Antilles, and pretty much every Pacific nation that isn't Australia and NZ.
nice quiz!
Then Venezuela decided to try to annex most of Guyana.
Sadly, now its easy.