I love Ultra's pose that is awesome and dynamic she looks ready to blast Agga to bits. How ever Agga is just standing there. In a film where there is motion, standing totally motionless in the face of an awesome attack is dramatic and cool. Doing the same in a still picture, you look like a decal pasted into the frame. She either needs to be warding off the blast or punching through the on coming attack. This will bring her to life in your scene.
Need to add shadows below Agga and Ultra as they are not part of the background and appear to be floating or just pasted over.
(Personal Opinion Choice, I would have had them towering over a city and covering the shadow area with skyline, and shooting from a lower angle, this would make them both larger and more powerful. Oh also I would burn Agga's shoes, they are just awful, leave her barefoot, she's too powerful for clothes anyway.)
Over all I really like the concept and the characters, this picture is a bit meh, but with some polish and work could become a really great picture.