I've been playing this for almost a year and am through over 800 levels. I used to have it rated as 5 stars, but recently, the devs changed it so that a benefit that used to take one ad to unlock now takes four ads. It's really disappointing to see because it was a bonus I was happy to watch an ad for in the past, but four is just absurd, this just makes me want to uninstall the game on principle. I hope they get enough negative feedback about their poor decision and change it back.