Agreed...
...Algebra, Trigonometry and Calculus were THE most draw-inspiring moments of my life and, judging from some of your drawings, I guess the homework was a pain to finish ^__^.
Anyway, nice drawings. Obvious metal slug influence in the beginning (which I like). Many funny and original variations: I especially liked the "standing" four-legged tank.
Some of the manga, however, has facial disproportions. Cloud, on the other hand, is awesome. (funny how they were done in the same year, though: 2006)
There's also one with a masked guy with long hair covering half of his face... looks sweet.
The mushroom ones are kickass.
Nice cityscape drawing (second-to-last picture in your sketchbook). It would be an awesome platformer city-map (with dozens of levels to beat).
Last... but not least... I love the sketchbook page-turning effect. Very clean, very smooth, very immersive.
Nice one!
10/10
5/5