Let me be clear - it is my own fault that I am disappointed with this game.
I had thought that it was a polygon puzzle type game in which you'd place pieces to "colour" the image.
IF you are looking for a very, very simple colour-by-numbers series of tasks of stylized images (polygons semi-abstract rather than realistic) then you may really enjoy this game.
I found it painfully boring. It literally takes you through the palette of colours/shades/tints for the image and you click on the assigned polygons. You can only click on them in order.
For example - the second puzzle is an apple with a small stem and a bit of reflected light. A simple, common image. The polygon art version (granted, this was only level 2) had 25 shades and tints of red. You do have the capacity to click on a colour out of order - so if you're feeling wild and wacky and want to jump ahead to palette items 23 from palette item 1, you can do so, but you can't choose which polygons you apply that colour/shade/tint to. (Again, at least not at level 2; that function may appear in later levels.)
I really enjoy some of the mosaic puzzle games, and I enjoy polygon puzzles and digital colour books, but I have never particularly enjoyed paint-by-number colouring, be it hard copy or digital. I want the freedom to make choices.
I did see that there is a choice to have some custom palettes but again, I admit, I only went to level 2 so I didn't see where or when that function might be applicable in this game.
I disliked the fact that I couldn't choose, even with an assigned palette, which polygons to fill with a particular colour/shade or tint.
There is no storyline, no challenges or other features. The music is of the sort that I find to be annoyingly repetitive but then I turn off the music on every game (and you can turn off the music in the settings of this game, so that's a point in its favour).
The colours are fairly clear, and after the filling-in is complete you can certainly see the ways that the shades/tints work together, so I gave it a decent rating for visual quality but it is inherently simple as it is polygon-based images. The one thing that could be a bit challenging would be seeing the numbers with more digits in the tinier polygons but the game does allow a zoom function so that a player can adapt for that.
I didn't find there to be any challenge, in fact I chafed at the lack of choice. Again, only the first couple of levels, however, so perhaps it gets better later?
I'm disappointed with myself for not having (a) read the description more carefully and (b) not having tried the demo first. I wasted a free game code but at least I didn't pay for this game. I cannot even imagine myself playing it when I need something simple to the point of almost being mindless to occupy a few minutes. For me, it's not worth the time it will take to open the game.
That being said, if you are a huge fan of colour by numbers and want something entirely guided, and find that kind of simplicity soothing, this may be a game you would enjoy.