Amazon didn't give an exact reason for the service's impending demise in its announcement. It merely said that it has created "new monetization opportunities for developers" since the program launched two years ago. "Developers can now earn revenue outside their game by converting game characters and imagery into branded t-shirts via Merch by Amazon," the announcement read. "And with Amazon Coins, Appstore customers can save on every game in the Amazon Appstore. Customers can buy Amazon Coins at a discount, while developers continue to get their full 70 percent revenue share." To note, developers' payment for apps downloaded from the Underground store is based on how long you keep their creations.
If you have an Android device from another manufacturer, you can only access Underground's free app store until this summer. In case you'd still like to like to try it out, you'll need to visit its official website on your phone or tablet to install it, since it's not available on Google Play. If you have a Fire tablet, you can access the store until it shuts down in 2019. However, you'll have to make do with what's already available, because Amazon will no longer accept requests to be included in the program after May 31st.