You'll be more likely to get a reply if you embed the image properly! (Copy the WHOLE link from imageshack)
Here it is:
In terms of your image, everything is very flat. The texture on the rock doesn't have any form to it (it looks like you've pasted on a flat texture, and not wrapped it around the volume), and there isn't a defined light direction to help you out.
The composition is also pretty flat - there is no distinct horizon line or aerial perspective to sell the scale of the shot.
It is very atmospheric, but it looks like a level from a platform game (2d, with small amounts of faked depth) rather than a photo of a 'real' 3d scene.
Don't know if that helps you at all - I would guess you have commited the very common error or trying to create an image out of your head without a lot of reference.
Look forward to your next version