Jim- I see what you're saying, I thought you meant on a down step the hand shouldn't be all the way forward (and it should, typically). As your number of frames start to increase, though, the precise timing becomes somewhat less of an issue because if you had, say, a 32 frame walking animation you'd have a good 3-4 frames of slack in the arm motion. Point being, I don't think it looks bad in this animation.
Abisso- Raising his belt is what did it. I didn't raise his crotch line when I raised the belt because it didn't really bother me, but if someone is bothered by penises then I suppose it's an issue. The winking effect is from his hair overlapping his one eye briefly, and a darker hair inline would help with that but I wanted to stick to the lighter ranges charles was using. Again, it's not something that would bother me or cause me worry.
charles- I think the new version is fine. You might make the symbol a bit darker at the bottom (a small v-shape below the design) so people know it's there, but aside from that I think it looks fine. The head motion is good, too, though maybe a bit too extreme? He almost looks like he's looking side to side instead of straight ahead.
I didn't remove any of your colors, I just altered the shades themselves.
As far as palettes go, I'm really not sure how to help someone colorblind. It's an interesting challenge from a teaching and learning perspective since I don't know how well you can perceive subtle changes in color like the ones I made. For instance, do the darker trouser shades now look very slightly red-gray, or do you perceive any difference at all from your original?
What I would recommend to anyone who wants to improve their color theory is to start with a neutral background color, like a neutral brown or orange-brown or red-brown. Those are predominantly what I use depending on the colors I intend to use, and the sprites always turn out having colors that work well on both bright and dark backgrounds and don't burn the eyes.
I think choosing a good neutral background is about the strongest starter advice I can give to picking good colors, in fact.
Next, I would say that even if you love primary colors to ultimately shift away from them as they tend to be very distracting and hard on the eyes. Here's a quick example of a sprite made almost entirely in primary colors (the skin tone is not):
The strong purple and yellow of the hair in particular are really overpowering and distracting here. So what's the solution? Mine is to mix it with a complementary color to dilute the intensity somewhat while also shifting the color every so slightly towards a more interesting shade. Take example 2:
Here I've shifted up the almost black outline to a reddish-brown, taken the pure yellow and added a touch of blue and about 1/3 less green for a slightly pale orange-yellow, I've dialed back the pure white ever so slightly while giving it just a tiny bit more blue so it doesn't look so stark white, and the pure purple I've shifted more into red by decreasing the blue about twice as much as I did the red. The colors remain identifiable for what you want them to be while being altered just enough to make the sprite easier to read and more pleasant to look at.
Hopefully that helps. I have a stronger understanding of color theory than I can really explain and it just comes with a lot of practice, so my advice is to practice.