Gun Control - Color Sketch

So I took the sketch I did a few days ago and inked it in Painter then threw in some color. I don't color that often so my knowledge of color theory is pretty poor and I usually pick the same colors. I just color for fun and prefer flat color. The inking in Painter was pretty basic. I made a few 'inking' nibs for myself and they give me an 'ok' line. Still feel that there is room for some tweaks on the nibs.