Wow...these are all really good drawings. And I see you've improved! You have a pretty keen sense of detail with your artwork. I lost when I saw Samus battling Bowser. And Black Heart mk.II? Insane. Seriously, great work. ( :
Are you still using MS Paint? With Gimp you can adjust the pencil settings and create a "MS Paint Pencil" and save other customizable pen settings.