I love the use of brush pen and thick lines in these drawings. You manage to convey a lot of expressions, even with good line economy, and the poses are fluid. I particularly like the drawing of the man with a stick on the second page. The strength in the pose really shows through and the slight tilt of head adds a lot of character and confidence.
I notice that in some of these drawings, the hips are a little narrow. Perhaps a few full body studies or even studies of just the lower half would help if that's a problem you are seeing consistently.
Using brush pen gives you a lot of room to use line weight as part of the composition. I can see this is already coming into play a bit with the creation of shadows and deep patches of contrast so you clearly have a knack for the material.
Keep up the good work.
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