The 3' face on the bottom page feels like the eyebrow and eyelid are not right, too close to the nose. The 5' face on the top feels like the eye on the right is too high on the face, the angle is just off from the other eye making it feel like the eye is floating. For the 10' face on the bottom, the eyes & other features feel a bit to high up on the head, remember the eyes are only halfway up the entire head - the skull is probably too low on top & shallow to the back.
BUT, I have to say I love the whole 30" page, the expression and personality you captured in such a short time is truly impressive. Keep it up 👏
Specifically, on the second and third pages, your ability to capture expressive faces in such a few lines is really impressive. I've noticed you have a tendency to let the nose get to large and proportional for the face. Your gestural drawing is really impressive though.
Wow, great job on these! I can see that you're already delving into some shading and highlighting. I think you're ready to move on to full portraits. Keep practicing with extreme angles and expressions, even wacky proportions. go wild and have fun!