The price: The 3.99 are more than fair, you get a full game (unfortunately without multiplayer), which has previously tasted on the XBOX 3 times.
The problems: The problems are to my knowledge only the Amazon Kindle Fire HD (no / bad flash player). This works fine, but the video sequences to be interrupted, and texts are not displayed appropriately.
Conclusion: The value for money is very good, the game super ("modern chess") and the replay value is high. Only recommended, a point deduction because of the problems.