The app may be free, but it is obviously created by money-hungry people or company. Ads longer than the game after EVERY SINGLE LEVEL! Only some ads can be skipped, but even then, it still takes 25 secs minimum before you can skip. Ads every 3 to 7 levels would be fine. BUT NO! Every time I play a level? And the levels are short (time between 30 secs to 3 mins). It's frustrating with so many ads. I'm deleting app because of excessive ads. Otherwise, perfect game.