What is the 15-Puzzle Classic game, how does it work?

According to the introduction of CussDev Inc., 15-Puzzle Classic is a Trivia game on the Android platform. There is currently a 1.4.0 version released on Nov 23, 2017, you can see the details below.

“15-puzzle” is a classic and funny game.
It may be also called “Gem Puzzle”, “Boss Puzzle”, “Game of Fifteen”, “Mystic Square”…
It is a sliding puzzle which you need to move all the tiles/cards back to their original positions.
You can play by yourself, or compete with your friends.

The features of this APP:
◎Support single player mode and two players mode.
◎Can select cards number
◎Provide the statistics of your records
◎Game Center supported

Make sure that third-party apps are allowed on your device: go to Menu->Settings->Security-> and check "Unknown Sources"

Tap the APK file. Allow the app any required permissions it asks for. Then, at the bottom of the installer window, click INSTALL.

You'll see a confirmation the app is installed. Now you'll see the app available in your list of installed apps.