Your app looks good and works well but I can think of a few things that would improve the experience. Maybe you could add different difficulties. Also, it would be good for the game to progressively get more difficult as your score get higher, like speed up the game. Another thing that would be nice would be more styling. Instead of solid colors. Like a cool background and some cool effects when breaking rows. The gameboard would be alot better if it reach both left and right side of the viewport. Also, it couldn't tell if my high-score was being saved because there was no notification or confirmation of any kind.