Uh. I've used MS Paint and a mouse for 2 years. I don't get where you're going with that, as most people went it comes to pixelart do use a mouse. The way you shade can always be improved by reading tutorials and the such. I really don't think you put alot of effort into your work, or they would be more original and full of shape. Please don't give that overly used statement about "I draw the way I draw." Sure, people have their own styles, but if they want positive exposure (Outside of their bedroom and school.) they need to improve what they do.
