Hi ! Good Job ! I think the pingouin is the most successful in regard of the exercise as we can see exploration lines and then more confident lines drawn darker. The girl looks a bit stiff to me. Lines looks confident but it seems you focused on the contours and we don't feel the flow of long dynamic lines showing the posture. The hand looks great ! Even if some lines feel disconnected, especially on the thumb side. Focused on all the details a hand have, you might have stopped drawing with your shoulder. I hope it will help you ! :) don't hesitate to share your thoughts on my submission :)

I agree with you, boots felt much more difficult than the others. Nice snail ! I feel the skull a little wide or not tall enough.