Looks like it could be promising if you pay to unlock everything – Colorify: Free Mandala coloring book for adults Review

There are a grand total of 6 colors you can choose from without punching (unlocking) the packets and as many pictures also, so it is extremely difficult to figure out if it is worth the money to purchase all the bells and whistles. And asking for a review before I have even finished my first picture! Come on! Totally not cool.
Review by vsguidroz on Colorify: Free Mandala coloring book for adults.