That looks awesome Chains, just finish the structure to the left.

Lighting all looks perfect as well, although the water at the bottom right of the waterfall looks weird.

That's probably your best piece that I have seen, the grass looks awesome. So do the rocks.

Get it finished with a nice clear sky and some alien bird things which Halo has. Or earth birds. You should so add a croc coming out of the water in the bottom right corner of the screen :P