:AT:

Many people does this kind of scene for action characters so is not the most amazingly innovative piece i've seen but yet the style, poses and bright colors match perfectly, i can't say the same about the background, even if has the looks and harsh style for this kind of image, the degrading gray colors leaves a white void at one side wich slowly merges with the harsh black and white character outline, the black lines at the sides brings certain heaviness and distortion to the focus point of the image (characters), the colors are live and vibrant but the separation between these colors and the background does not bring enough contrast making it look like the border fades the farther right you see, the character's lightning does not match, the left side's has smooth, heavy lightning as the right side's has weaker shadows and rougher lightning lines due to to this, the right girl has less contrast with the background making her harder to watch, a little suggestion could be taking out the sidelines, using softer, smoother lightning(as the left girl's pants to the right side's hair), shorten up the thickness of the blackish line and adding a bit more of white so the line will contrast better with the background and adding more heavier, darker but smooth shadows to the right side's to match the left side's and highlight the character more.
...or just making darker the right side of the background and leaving the dark lines behind the characters; I noticed that making the right side darker, there will be a spotlight at the middle of the image between the characters, you could leave a crossed degrading line in the middle of the image to prevent the background to become too dark without causing a major impact on the image