5 stars: 1000s of levels. I play it on all my devices. My favorite is the Levels-side gravity mode. The UNDO bar at the top right lets you go back as far as start-over and try another strategy to score more points. A few times a level didn't keep my place when I closed the app to recharge---not a serious problem---it can't keep me from playing. Enjoy the challenges and relaxing/stimulating my brain.
4 stars: Difficult ads. The recent version presents ads with no way to get out and no timer. UPDATE - Thank you for the feedback on the adds. My daughter and I like to play this while we are waiting for stuff. I want to support the developer and also want to play the game. The provided information she help us do both.
4 stars: I've had this app for a while and really enjoy it. However, the new ads are frustrating. I know they cycle through every few games, but they're too loud and hard to end. I understand the need for ads, and have no problem having them, but the current ones are irritating. Lose one star for that. (And I'm actually playing the app less).
3 stars: I used to love this game but the new update with so many ads is annoying and what happened to the fireworks when you completed a game. Thinking of going to another game with not so many ads
2 stars: Have been a fan for years until now - the ads have totally ticked me off. I would have paid to get rid of them - but there's no option to do so.
...