Time killer for sure, but too repetitive. Add different levels.. Like level 1 with 4 squares, 2 with 6 squares, 3 with 9 squares, 4 with 14 squares, 5 with 20 squares, 6 with 28 squares, 7 with 38 squares, up to 10 levels maybe? or, after 10 levels, there is more than 2 colours.