Nice work. I would recommend focusing more on capturing the bigger shapes and angles in the figures and less on the individual lines of body parts. It looks like in the 5 minute drawing, you allowed a little more time for finding the underlying shapes before fleshing out the lines, and somewhat in the torso parts of the shorter drawings, which is great. I'd try to do that more for the extremities on the shorter drawings as well, and don't be afraid to let those drawings end up looking more like collections of shapes without a clear outline, rather than outlines that don't show as much volume.
