Great sketchbook, I really like your bold use of colors! The female with the rifle is my favorite on this page. Something about the values and simple shapes make it easy for the eyes and the palette looks great. On the purple and blue city environment, I think the horizon should be higher, it looks like there's a huge wall with clouds painted on it in the background. Your characters sometimes have stiff standing poses, like knees locked on this one and this guy lacking some sense of weight.
I really like this older environment piece too! Keep them coming!