Some good stuff there,
It's easy to see you've greatly improved as the drawings go on.
The soldiers with the guns are the 'best of the bunch', you seem to have good knowledge of basic anatomy. Your early sketches look like you were just practicing different methods of art, and it shows it's helped by the appearance of your later drawings.
Your drawing of the arm is good, and my favourite pictures out of them all are probably the soldier kneeling down, using cover or reloading, I can't quite see, and the soldier pointing.
Your Spiderman sketches look like the legs and feet are twisted around, and they don't look right at all i'm afraid to say. The drawings of the eyes you've done are also good, maybe trying a slightly darker pencil on these eyes will help bring out the detail, as they are light.
Now for the best piece of work, the bag
I've always wanted a proper artists bag like that. Is it specially made for artists to use, and where would I find something similar? An art store maybe?
Anyway, good work overall, keep drawing, and it's easy to see, over time, you will be extremely talented.
- The Lost Wizard