I purchased this app for my Kindle Fire HDX. There were several technical problems with it, and additionally, it was too hard for my son.
My 3.5-year-old loves everything the Kratt Brothers have done, but the games on this app were too fast for him, and hard for him to accurately control. There also wasn't much to the games, and they weren't particularly educational.
However, the bigger issue is that the game just generally doesn't work properly. It crashed repeatedly when I tried to load it in Free-Time mode, so he had to play it without parental controls on. The audio tracks are unbalanced, so sometimes the music is glaringly loud, and you can't hear the voice track explaining how to play the games. Lastly, the rewards for playing the game are picture scenes where you can insert yourself using the camera on the device. Well, on the Kindle Fire HDX, they have it programmed upside down, and no amount of turning the device around would put us right-side-up in the pictures.
This app was certainly not worth $3 with all the technical issues, and would have only been worth $0.99 without them anyway. I've noticed many of the PBS apps have issues on the Android platform, which is a shame because their television programming is so superior.