mark1707: The cave shot looks fantastic. Very interesting layout. It just looks a little weird with the very green plants growing out of the grey rock. I don't think vegetation that lush could grow in there. The same can be applied to the third screenshot-the vegetation looks so healthy compared to the dull brown of the rocks and dirt. Also, I'm curious about where that waterfall is coming from.
The second screenshot has a good layout, but like Me(tm) said, the lighting looks weird. Use just white or a duller orange because it doesn't look too good with the rest.
Those are impressive, though, to say the least.