I don't see any big problems with this. It's nice! I think it does lack an appreciation for forms and shapes in some places. Instead of drawing tons of little squares for texture, think about what sort of texture dirt has, and how light reacts to it. Clumps and cracks and shadows all appear in a multitude of ways, so don't stick with just one yet. That said, it is a stylistic choice. There's no surefire way to draw dirt right, so there's no need to change it if you like it.
Try using cooler colours for the dirt as well. Naruto is orange and yellow, the game should compliment that for readability and prettiness.