La bomba..Rendering exercice

I did this while i was in class.. bored.. so i didn't emphasazie on design, but more on rendring.. plz, i need some criticism. Dont try to be nice and only say "its nice" lol.

http://img393.imageshack.us/img393/6589/image35re.th.jpg (http://img393.imageshack.us/my.php?image=image35re.jpg)

You did that in CLASS? I wish I could doodle that well.

great job

Well my class was 2 hours long, and i had several markers with me, as well as a ruler.. lol :P
I know it doesn't look as good i i wanted it to.. but i dont know what should i improve.. or on what should i concentrate next time.