The wall paper is really easy to use, settings are Clearly Explained: how to interact with the fish, feed 'em, grow' em, it is creative, zen, the animation is really well done. I Had tried the free version, After two days you-have a limited version if you want the full version (the full choice of fish, the change of backgrounds, how to feed and grow 'em) you-have to buy the live wallpaper. This is really a good choice on my Nexus