Excellent and interesting quiz, nice job.
Replayability is possible but it would take months to design. I will start working on a replayable version soon.
As a suggestion, maybe the gradient could be across a couple different colors to make it more clear? I realize that some people have colorblindness issues with certain hues, but just a thought.
btw, the quiz uses urban population. i'm sure the city data is correct
But seeing as the pinned comment got a good amount of likes, I'll make a sequel
It's the same list I used for my 500 Biggest Cities quiz
But I enjoyed