I agree with SalStrange review and the other review regarding poor choice for spending coins you accumulate with each completed puzzle. Too much spam, too many windows to get back to your puzzle screen, and the worst yet? Now there are these FORCED game type challenges that do not allow you to close it unless you play. I purchased ad-free and hav loved this game for years. I do buy alot of new puzzle packs; I play this game every day to decompress. So it really takes away the fun to be force fed spam in the game. Keep it in there for those who like that type of thing, but for the rest of us, give us a way to opt out of all of it in the PAID version and just let us enjoy the game.
I started searching for a new game tonight, but I really hope the developers listen. I only have three games, this one, a card game, and a slide game I have had since 2010. I use them to decompress, and sometimes play room type games like the old Myst game.
One final note, oddly, this game no longer shows up in my Apps list in settings, nor in App store under updates (I dread the updates because its always more SPAM, MORE SPAM, MORE SPAM. What a wonderful almost real jigsaw experience ruined because you can't turn off the developer spam.