Those are very good. It would be nice if you mentioned the time you had while doing these gesture drawings, but it seems like 60 seconds.
Given the overall quality, the confident anglar strokes, you most likely understand what your weaknesses are, it would be proportions. It comes with mileage, so just continue doing what you do. Later you might want to begin to incorporate some shading too, when you feel more confident about your proportions.
