@RocketKnight It's really interesting. I assume it flies? Otherwise the arm mass vs leg mass makes no sense. You should use the same light source that the character does (above), get rid of all that pillow shading, and maybe color some of those black outlines.
@misakoc That's good to hear! I hope I can continue to be helpful.
I think both of your images have strengths the other doesn't. The left's bolder outline will help it stand out on more complex backgrounds so the image doesn't get lost as she moves. The crisper details will also help with that and it would be much faster to draw. The second solves a lot of the problems of the first, toning down things that were too harsh and removing the stair stepping problems, but I think you've gone too far the other way. I think it has too many colors now (if you're going for that many, why do pixel art at all? Play to the strengths of the medium), and some elements are over blended. This is especially obvious in the outside edges underwear, where the antialiasing is so strong it looks like paint instead of clothes.
How easily and quickly you can make something shouldn't be understated. Animated battlers have a LOT of poses, and many elements aren't on screen for very long. It isn't an area where spending a lot of time being picky about pixel placement is going to do you a lot of good. Animation is also something that works best if you get it all mocked up and moving before detailing. If you spend a lot of time on one frame before it's complete you'll end up doubling your workload or more from redraws.
She's a cute kid. I especially love the freckles. Someone that heavily freckled wouldn't have them only across the face, put a few in other places that get a lot of sun, like the tops of the shoulders, the forearms, and maybe the top of the knees.