Flags of All Countries of the World

I already have 5 separate apps about all countries on all continents. They range from very popular European Countries to Australia and Oceania that is lagging behind. The idea to combine all countries in one comprehensive app seemed reasonable. My new app Flags of All Countries of the World accomplish this in respect of national flags.

The English description of the game is the following:

Why do I prefer this app to many other apps about flags?
Because it has all flags of all 197 independent countries of the World! It is extremely user-friendly. You will always get a hint whether you’re right or wrong. Thus, you’ll never get stuck by the question for which you don’t know the answer. Choose the game mode and find the state flag of your country:
* Spelling quizzes (easy and hard)
* Multiple-choice quizzes – “challenges” (also easy and hard)
* Time game (give the most answers in 1 minute)

*****
The user has to give 50 right answers in the easy spelling quiz (the easiest flags to guess) to access the hard modes. Two multiple-choice quizzes have different sets of flags and separate leaderboards in Game Center. The Time Game includes all 197 flags and can be opened after an IAP that also removes all ads.

Acknowledgements:
icons for buttons were downloaded from iconmonstr or were created with Font Awesome.

Thanks!