My ideas are a little more basic. I think it would be wise to break this things down to the composition/message level. It seems to be lacking in focus. It is confusing and the message is not clear. There are some design elements that are rather dispersing to the eyes and therefore confusing to the viewer.
For instance you have lines of action and motion that are confusing and conflict. You have the motion of the main character, he is causing something to his right.
Just above that you have a line of motion coming out of the ship and wizzing by him, just to the left. Then along the right another line of motion.
Then the explosion near the ship and finally some particles coming off of the back of the cart or whatever it is in a very dispersed way.
There is nothing wrong with Chaos. But for advertising it should be used to your advantage. You need to have a clear focus point to the image, it needs to have direction and should convey a clear visual message.
My suggestion would be to google movie 1 sheets and book covers. See if you can find some common elements. And be critical because they don’t all work. So try and see if you can pick out the common elements that make the good ones work and the bad ones not so. And use those to your advantage.
Here are a couple of examples and my analysis:
In this one, see the chaos of the masses at the bottom. And the fire. Then above that you have the main focus on the characters in front of the flag.

And this one notice how the lines of motion are all aligned with perspective of the buildings and the main focus again on the characters: The lines of motion all support a focus in one direction and your attention is then drawn to the main characters.

And this one notice how you could draw a few simple lines though it.

Take a look at these:
http://www.openflame.com/harrypotter/book_covers_all.html
This one for instance.
How would yo draw the lines of focus through this one?
http://www.openflame.com/harrypotter/harry_images/covers/book4/cover4_b_french.jpg