More contrast and less noise IMO.
The colours on the old sprites are great so I don't know why you're straying from those.
I think you could benefit from rendering without texture first.
Then rather than just adding noise, try adding some more subtle variation across the gradient to create some texture, especially around the mid-tone areas.
It doesn't help that your light-source appears to be front-on in some sprites, and from top-left in others.
You can get usually away with flipping sprites and their light-source along with it, or you can shift the global light-source to be more from the top-down.
Either way, flash-photography isn't very attractive looking, nor does it do your forms any favours.