Sorry in advance if this sounds like I'm ripping it apart - there are some fundamental problems with your mockup.
Basically it seems like you are fighting with the natural way of visually communicating. You have tiny, low contrast, low saturation foreground images that you're trying to make stand out against a high color, high contrast background. I would start by lowering the contrast of the background and making the colors more subtle. If it's supposed to be at night there should be a bluish tint to everything, not just the sky. I don't think it would hurt to make the bombs bigger and give them color - make them red, maybe, or something else that will be easy to see.
I would make the lives/score bigger so they fill up that black bar, too. Right now there is a *lot* of wasted space there - you're only using half of the bar.