My favorite Android game has always been, and still is, OSMOS. It used to be in the play store. You can still get it on Android from Hemisphere. There's also iOS, Ipad, Steam (for Linux), OS X and Windows versions. I love this game so much I keep an ancient 7" pad with Marshmallow 6 offline just for it (Because I had the original on it - You don't need an ancient device).