It looks really nice!
The black lines suck though. What I like to do for nature backgrounds is get the fill of the object, and make the outline like 4-10 shades darker. It comes out really nicely.
If this is a trailer, it doesn't give much information. I have no clue what this is about. If you do anymore trailers, try to make it give a just enough information about the characters and what is going to happen to make the viewer want to see the rest.