World: Large Countries - Map Quiz Game - Seterra
Even though there are 195 countries, some stand out on the map more than others. Russia, for example, is just over 17 million square kilometers, while the Canada, the United States, and China are all over 9 million square kilometers. Identifying those may not challenge your geography trivia too...
online.seterra.com
Game tells you a country, you need to click it on the map. This particular mode asks you 50 countries.
I completed the round in 2 minutes and 37 seconds, and got 79% of the countries correct.