So after some testing others games and my own a couple issues have come up you should know about if you are publishing your app. If you remove the permission "WAKELOCK" your game with crash on start up on some devices.
Also there is a new bug using compiler version 2.1.1, that on some devices the game will crash at start up as well. Ludei knows about it and is working on it. It has to do with the gyroscope/permissions. The bug report starts with:
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.fontor.pongpang/com.fontor.pongpang.PongPangActivity}: java.lang.IllegalStateException: There is no way to start any rotation management: no sensor fusion, no rotation vector nor orientation handling found in the system