If one were to start this puzzle with one of the colors instead of the black outline, it might have been a reasonable challenge. But I started with the black, and while it did take some logic to get all the black right, after that it was just a fill-in-the-blanks situation. No variation at all among the greens and yellows, just a coloring book-like picture with solid blocks of color. I found it disappointing. The second half was so predictable I barely even wanted to finish it.