Well done! One suggestion – perhaps 'Guinea' might be considered a valid type-in for 'Gulf of Guinea'? I believe this is the case with other featured quizzes.
Amazingly, Lome is about 175 km from two other capitals: 175 km from Porto-Novo, Benin and 173 km from Cotonou, Benin. I didn't notice the word "west" at first, making the answer Accra, Ghana.
All capitals should be 175 km apart. But then there would be 157,000 countries. JetPunk, start working on that quiz: time limit is 24 days, but you only have to get 94,000 right to score a 5.