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Here's the thing about doing color, if your going to make a simple game like this. One you should give different shade options for each color. Best channel to compare for shades is the HVS (its also known as the munsell system). It gives you the opportunity to create different Values and Saturation with in the same Hue. If you give three shades choice per each color you can create the ability to create simple depth in the painting. Also it will give the user the feeling that their are a lot more colors (even though they all lie in the same hue). Also some of the choices are great, i.e. the flowers petals have to be the same color as the center and there's a few objects that are the same way. Creating the different shade options you can break up objects like the tires that way the back ones can be a darker shade then the front ones, giving more feel for depth. IMO its a simple game, put more time in it and even for a simple game it could be kinda fun.
Under rating threshold (hideshow)
XP in my endeavor to paint everything the same color, i found that when you paint the fuel-door, the black outline disappears, the word STOP can't be painted, the center and some of the surrounding blank spaces of the steering wheel can't be painted, and a frew of the smaller lines on the car aren't printable.
Other than that, not bad, for what it is. (maybe try and add more than just one thing for people to paint?)