Luffy and Zoro

I can't call this a quick sketch, because I put so much effort into this thing. But unfortunately, as you can see, I started drawing this on the back of my physics worksheet, which I kind of regretted later on... I usually do this, too. I'm always afraid of wasting perfectly good paper, and all my artwork usually ends up on crappy paper, like this one. *Sigh* But I hope you ignore that. I'm quite proud of this, although there are some things in here I wanted to change. For one, when I looked at it from a distance, I noticed too late that Zoro's head looked a little big...ehehehe... But otherwise, it looks quite good, no?
Also, notice that at the end of a good battle, Zoro pulls the bandana off his head, and Luffy puts his hat back on, so I portrayed that in here (except it's hard to see that Luffy's putting the hat back on. the point is that I tried).

Anyway, please tell me what you think! It's very hard to know the quality of one's work if the judge is the artist alone.