I think you used all your points to max out color and shape skills. 
Your colors and light environments make the illustrations look interesting and fun to look at.
To me it seems like the other fundamentals like values and anatomy aren't on the same level and make things seem a bit off. Your faces are nice but the body and hands seem a little stiff. For the values, some areas are really light even though they're not the closest surfaces to the light source , like the girl's knee or the guy's arm. Also his face seems bright despite it facing away from the light source.
I don't know if you've seen this video by Marco Bucci, but he talks about how some digital color triangles/squares mis-represent colors and their values. He also mentions why using a saturation layer isn't an accurate representation of the values for color.
I made a comparison with your pic to show how different ways of viewing values. If you view it through "proof setup" it'll give you a more accurate look.
It might help to do some grey value studies with basic shapes and blobs and then do more with with color.
