Proto and Metalman look great.
And, not trying to sound like a dick, but you probably should have done some really light outlines and laid everything out before going crazy with the tiny pixel block gears. Other than some of the background looking kinda wonky, though, the characters look really good, might be some of your best work in my opinion.
Yeah, I'm actually considering cutting the characters out with photoshop or something and doing the background on the computer.
But the 'pixels' were never meant to be very accurate anyway, so I'm not sure.