Ahh... I like this. This is very inspiring work...both the scenery in all its minimalistic beauty and the Colossus itself.
In fact, the sheer size of the beast compared to the tiny human on what I assume to be part of a humongous tree below it is one of the most inspiring parts of the image, as it has led me to an idea of how to create and express a massive and detailed world such as would be necessary to really...provide for the amazing and horrific might of this Life Colossus.
While simple, this is an absolutely amazing image with a mighty soul all its own.
As a side note, it looks strangely reminiscent of Anubis.
I gotta say, I love how to executed this! The different shades of green make the sense more mystical than terrifying (which I'm sure it is for that poor guy down there. xD ) This is a great change in pace for what you draw as well, it's always nice to know an artist is flexible with what they make. (: Great design, good luck in the contest!