Typically, the first video for each song is free, with the additional sections costing a few bucks a piece. Yep, this keyboard comes with in-app purchases. This felt a bit cheap to me -- especially considering that the exact same "HD Piano" videos are available on YouTube for free.
The same goes for that interactive sheet music I mentioned earlier. You get plenty of classical selections to practice with for free, but if you want to learn how to play the latest Taylor Swift song, you'll need to fork over a couple of bucks.
The good news is that there's plenty of free content across all of the app's features -- enough so that I felt more or less satisfied. I wasn't willing to pay to learn the outro to"Hey Jude," but since the intro/verse was free, I didn't come away feeling too upset about it.
As for the game mode, I found it to be a fun and clever way of testing your skills. There are dozens of songs to choose from, which felt like plenty, but most if not all of them are folk songs or holiday songs aimed at kids. I'd prefer a greater diversity of options.
You'll also find additional practice games hidden in the settings menu. The ear training mode offered an especially interesting twist on training: the piano plays you a note (or, if you're up to the challenge, a chord), then asks you to go and find it. That's typically a pretty tough skill to develop on your own -- with the app, you have a helpful partner.
I like this thing. It isn't going to beat the one-on-one instruction you'll get with a good piano teacher, but it will provide you with a way to gradually improve your skills, and a way to have fun doing so. It's better for kids than it is for adults (I couldn't help but cringe during the first lesson, when the instructor sang "Hot Crossed Buns" to me), but still offers enough to encourage anyone with an interest in learning piano to sit down and do so.
At $300, it's far from the nicest keyboard that money can buy, so if you have more serious musical aspirations, then look elsewhere. But if you or your kid is a beginner looking to learn, well, there's an app for that, and a keyboard that goes with it quite nicely. Give it a shot.