The game itself is enjoyable. I like the mental exercise, but this game is an ad app with short breaks of the game. An ad after every single level which take less than a min to solve. The ads are skippable, but you have to click a tiny button 3-4 times to close the ad. Tapping anywhere other than that tiny button gives them ad revenue and sends you to the play store. Game was enjoyable after I modified the apk to remove ads.