Modality cleverly enables you to earn plenty of digital trophies along the way, which you can view in your "trophy case." Even though my daughter didn't play long enough to actually progress through all the rounds, she did enjoy showing off and admiring her trophy case. And, of course, the fact that there are many rounds is a testament to the sheer quantity of content stuffed into each of the games.
The content, as anyone who's familiar with the card decks, is of a very high quality. My daughter's only complaint was that some of the questions were in areas simply not covered in her second grade class or contained concepts still unfamiliar to her. It's a valid complaint, for those who play the game. However, since there's no standard national curriculum, the only apparent solution to this problem--to only include a narrow, shallow group of questions representing the lowest common denominator for each grade--would fail to be very educational.
Modality has done a terrific job of transferring the Brain Quest experience to the iPhone. It's not easy to replace to the tangible feel of the cards and a progression through a deck; Modality was wise not to try to replicate that experience, and instead to work with the questions and "spirit" of Brain Quest as a starting point for a game that encourages sharp thinking.
My daughter, who has a moderate amount of computer gaming experience--but mostly with "casual" games--understood the game's interface quickly and easily navigated her way through. In this fashion, Modality succeeded in making the thinking part hard, and the game play easy.