This tut was actually a pretty interesting one to dig into. It brought me back a lot to the abstract days of kicking around the studio art degree at Whitman; it gives you a lot more creative challenges.
A couple of net adds I think that enhanced it were a few background textures to make it more 3d, I darkened the sky, added a few more clouds, tossed in lightening, reduced the amount of rain and ultimately kept some color in it.