I Love it!
Wow!
I do my pixel art the same way, MS Paint and Mouse.
Really awesome work. I still need to use refrences too, if I was trying to do something that small, it'd probably take me longer to do than something big. (My reason for this is that I get into detail and something small dousn't allow for as much detail)
Grate work! I look forward to seeing what else you can make!