I paid for no ads in between games. I figured watching one ad to get an extra tube was nbd. Now I have to watch 4 or more ads to get an extra tube. Also, difficult game sets start repeating after level 1500. I ended up having to watch so many ads that I uninstalled it even tho I paid for it. It was not enjoyable anymore. Greedy Developers? Maybe. Unhappy customer? Absolutely.