One of my colleagues (a middle school prealgebra teacher) sent me this email about the App:
I bought this app ... and played for over an hour straight (and I don't usually play games on the iPad)! Showed it to my D period yesterday on the doc cam. I let everybody have a turn and a handful of kids told me they were going to play it over break. Good app to make pretty abstract ideas about manipulating equations much more accessible and (gasp) fun!.