All Countries by Area with letter hints as you go along: 6 Minute Sprint
List all world countries in order of size. At the end of each answer you are shown the initial of the following one.
Every time you guess an answer, you will be shown one letter from each of the 4 answers below (the 2nd letter of the answer below, the 3rd of the answer 2 places below etc). This means that reading 'diagonally' (going up-right, starting from the answer above the one you're looking for) letters of the same colour as the rank number you'll be able to get a good hint (but not the initial letter!).
Area data from wikipedia, country names from 'Countries of the World Quiz'
For a version where the appearing hint is just the starting letter of the following answer, try this quiz