My daughter is almost 4, she is getting very frustrated with the pace of advance in the app. She is distinguishing pentagons from hexagons one minute and then asked to "pick the squares" (from a choice of - yep - just squares. Not very challenging.). Easy stuff she has previously mastered keeps coming up again but the stuff she finds harder rarely even pops up. She is already almost as good at the hidden animals game as I am, and just exits out every time it appears because its "boring".