That is a great question! Although we love to have developers publish their apps and show us all of their new and innovative ideas on the Amazon Appstore, the GameOn service does not require the app to be on the Amazon Appstore. GameOn can be used on a game that is on any store, or any platform (mobile, console, PC, etc.) as long as you have access to https calls.
Best game on Amazon for <$25? 1 Answer