First choose a level by typing ‘beg’, ‘int’, ‘adv’ or ‘exp’ – beginner is 10,000,000, intermediate is 5,000,000, advanced is 1,000,000 and expert 500,000. Then, begin naming cities. All cities of 10K+ population starting with the city you chose and moving outward will begin filling in until you’ve hit a total population equal to or greater than your chosen level’s threshold. For example, if you choose ‘int’ – the threshold is 5 million. If you choose ‘paris’, then Paris will fill in and because its population is under 5 million, successive cities moving outward from Paris will fill in until the total population reaches at least 5 million. If you chose Moscow, only it would fill in as its population already meets your threshold.
Enter level to begin ('beg', 'int', 'adv', or 'exp').