It's an okay puzzle game, but having to watch an ad after every restart when you're out of undo's and are only getting two or three moves in before you want to restart ruins the enjoyment. It ends up being more time watching ads than playing the game, and that happens in the first half hour of gameplay. I'll buy ad-free if I like the game but not if you try to annoy me into it. This is a cash-grab. Uninstalled.