It is hard to put solid criticism on a series of subjects that are both personal and abstract. (doing uncertainty first was a smart move on your part) But based on what you've said so far, the only criticism I can think of is that maybe you aren't using your bold palette to its full potential.
The coloring is solidly and logically done, but the image lacks texture because of it. I always thought the appeal of pop-art stemmed less from the actual colors themselves, and more in the ways that those colors crossed over and intersected with each other. It's funny that you just now made this topic, because what you were setting out to do reminded me of an art book that caught my eye because of the type of style it was trying to teach.
I'm sure you've seen the style somewhere before, it's all about taking open solid spaces and intersecting it with varying binary patterns of visually stimulating variety from simple to complex. All I remember about it is what it looked like, and that the term for this kind of art was a weird word that is next than impossible for me to remember even having recently read about it (which is a shame because I bet it would be super-easy to look up if I could only remember what its called). The closest recognizable analogue to it I can think of is the type of skull decorating that is typically done for Dio De Las Muertos festivals. I don't have my tablet on me, so all I can do is take a photo of a sketch I did to try and explain what I'm referring to visually.
Yeah, if anybody knows the name of this style I'm trying to remember the name of, please tell me.
EDIT: as it turns out, the reason I came across it recently was because it's actually a recently released book! The exact book I was looking through was in fact the first result that popped up on an amazon search I did right after making this post.
http://www.amazon.co...words=art books (of course it's simply the combination of the words "tangle" and "zen", which actually makes it a reasonable name for the style)