I downloaded the game and bought a small package that has all countries available (plus flag and capitals). It has 3 levels of difficulty, which allow you to learn a smaller amount of countries before having the whole continent (or world if you wish) for you to guess. It also has a study mode, that you can use anytime. It’s especially good after you play, so you can revisit the places you got it wrong. I’m totally satisfied with the quality and possibilities the app gives! 5/5!