Not trying to be an ass, but, before I get into any critique, I want to suggest that you consider your tone for a moment. The whole "don't bother me about it." comes across as "f*ck you, I do what I want. I don't care what YOU have to say." That's the wrong kind of attitude to present to someone you want to help you, much less to someone you actually want to hear what they have to say. I almost chose to ignore this thread for that reason, but I figured you probably weren't aware of how you came across. I decided to attempt critique anyway because you've got a fairly good start on your sprite there. In the future though, it's enough to just mention the drawing isn't yours. Nobody here would bother you about it after that.
It might also be worth mentioning that drawing with pixels while referencing the 'reference' may have been better than shrinking the image down and pixeling over it. Not sure how proficient you are at drawing, but you can only get better with practice. ;P After all, the construction of the knees in your 'reference' drawing's line-art is off. That poor construction translated down to your sprite upon pixeling over it and now its (our) right knee is too low, making it more pronounced in your sprite than it even was in the original drawing. Look closely -- the top of the knee on the right in the original drawing is much lower than the top of the knee on the left -- and that's not perspective distortion. ;P
I'm not sure if you were going for the Street Fighter Alpha 3 style since you put Ryu there as a comparison, so I'm going to switch to general critique mode on this one for now.
Anyway, the first thing I notice is that there's no real light source -- at times it looks like it's coming from the right such as on the (our) left boot, but the thigh suggests it's coming from a different angle altogether and isn't following the 3d form of the leg either.
Additionally, there's no need for a second shade here unless you boost the contrast a lot more between the shades in your color ramp. Atm, I think you should add in a fourth "buffer" color that blends between the highlight and the spread-out light on the body. It doesn't look a lot like an SNES sprite as it is with only 3 values per 'color' on the sprite. You'll be surprised at how far that 4th color goes.
Finally, there are some single pixels that are out of place on your pixel-lineart -- it's best to smooth those out, otherwise your lines just look jaggy in places. Look at the (our) left foot where the ankle and top of the foot touch. Also the elbow is too sharp with that added pixel on the tip. And finally, that left knee again (bottom-left portion of the 'oval'). This will help you clean it up a little hopefully. Look for places that just don't make smooth curves also (such as the back of the helmet) to ensure your lines read properly.
That's all I've got for now. Hope we're still pals. ;P
