Hit! These guys can play any hit for you! It's more than a "piano like" application and it's more than just a funny toy for you and your kids.
There is a possibility to register your tries and then replay them or to launch a child mode which will highlight step by step the necessary notes and thus will allow your child to replay the previously registered tune all by himself. If you don't bother the characters during some time, they will start to rock after a while (apparently because they got bored).
Please read help before usage.
If you met any difficulties with this application but you intend to use it in future, please let us know about them by e-mail.
P.S. Thank you for your responses.