This game was a fun differentiation from regular sudoku at first, but after a while I realized the same 3 colors are always together within a block. It's almost impossible to lose knowing that, which takes away the challenge. I can solve the hard puzzles in about 2:00, and that's just because the color squares move really slowly on my iPod. Aesthetically, I do like this version of color sudoku a lot more than others, but the puzzles take almost no effort to complete when you know what color combinations to expect. An update making sure the colors are randomized a bit better would help.