Very nice, you have potential :)
The animation was superb, but your choice of colors and your art is lacking.
Before starting Green Chronicles II (which you better make) I suggest you practice drawing. Take time to study lighting and color choice, both of which are crucial in making something look realistic. A general rule of thumb is to stay away from basic colors like the hardcore green you used on the main guy, and use more exquisite colors. Play with the color mixer and don't be afraid to expiriment.
Sound was amazing, the fighting was well choreographed (I loved the chase scene), but it could have done with a little blood :)
Very good work, leaves me wanting more.