Its to simple. Spice it up. Add background, effects. I don't care if you wanted the 'I'm a plain guy' look, make something that is appealing. I know I am a dick but it makes people think. Also explore colors.
actually ohgasm coming from a design background it's more appealing than your current in many ways it has flow, asymmetry, and colors that go together and yes white is a neutral color so I am not saying he gets the point there. My critique is that it's over sharpened in some of the areas like the splash and that the fade on yoshi seems to distract the eye like a white man in the million man march lol but other than that it's a well rounded piece
