Hey Ralph,
Nice, like the atmospher that are coming from the image, you have really strong and interesting elements on your image, a cool magical mistery tour 
Perhaps you can add a fog layer from the city to the background hills to gain in deep for the image and look more far the giant broccoli, Mr. Pineapple and the city, now the elements in the image look a bit in the same plane.
Maybe yo can add contrast for the foreground elements. If you guide by the sun light over the sky the light is coming from the right and back side of the background, perhaps some casting shadows and more contrast on the broccoli and the man on the left side of the image can help to put more distance and enviroment effect on the image. ( Are you the guy of the image? :D)
I dont know if giant broccoli can grab some airplane or building in one hand, think that can be a nice touch (more than a critic is a wish… hahahahaha :D)
Cool work, love that broccoli mutants ! Cheers!! 