Today's Free App of the Day is Creatorverse
This looks like a fantastic game; I'm downloading it now. Create your own colorful and creative Rube Goldberg type machine in this clever physics game. Good for budding and would-be engineers!
There is one three-star review which complains about not being able to move the app to the SD card (on a non-Fire).
There is a bit of a learning curve. An on-screen tutorial would be nice...you can also call up other people's published creations and check out how they work. But I did find this:
11 of 12 reviews are four stars and above.
These apps are compatible with the original Fire and with my Fire HD 8.9" 4G. To tell if an app works for your Fire HD or other Android device registered to your Amazon account, click on the above link and look on the right side of the web page. Amazon will tell you if it will work with your registered device.
Also check out the other digital deals from Amazon, including great deals on MP3s and videos: