I can tell you one thing: your current palette is hell. The jacket works so well it is just almost worth it, but in the end a lot of restructuring is in order if you want to do all you can do with it. Looking at your (old, but still) stuff closer, I have these crits that I believe are valid and you should give them thought:
*pixel art is a precise art form. Every pixel needs to be placed with intention. Right now, you're too messy. You look at your stuff too much on 1x zoom (am I right?) and it works there but what bars good pixel art from being great pixel art sometimes is the extra sheen of smooth people (like ptoing, not me so much) put that you don't see in 1x (but which you see in 2x) that almost subconsciously make you feel 'this is smooth, this is deliberate'. More precise pixel placement. AA everything you need to aa. If you have lines that have 3-4 levels of lightness difference on surfaces, and you've not yet AAed them with buffers, you should ask yourself why you're not doing this. Pixel art can be a naturalistic medium where everything is equally detailed and BLAM in your face intense, or it can be a medium where attention is diverted to places with more information against more blank stuff. In either case, where you DO have pixel information packed tightly, your skills need to be uber-extra tight. Every pixel in it's right place. This is the quest, and it will take you as many years as you put into it.
*different planes of lightness. Under the neck it's darker than on the brow, and therefore you START with a darker base regardless of what tints on information you later on pack in there. This is important in ever level. Items have volumes and are faceted. Study the face as a collection of geometric shapes, and give different planes initial values that aren't all flat. If you're coming from a comic art or manga art of anime art background: forget. Look at objects as collections of primitives like painters do, and don't rely on hisaturation unless you're making a point with it. If you have too much white (or too much black. Guilty Helm? Guilty) and it's not a stylistic thing, you need to think about why you're doing it. Like when someone takes a hicontrast photo of something, or posterizes, things are easier to draw like that, but you strip away a lot of the challenge. Tone your lightness values down, and do it the challenging way: show brightness through juxtaposition and contrast where you need it. White is the 'I put a specular highlight here, tee hee' color, not a big surface color. (some of the time. I think you should try)
*forget selout. Break outlines in relation to how 'thick' the contour you're trying to express is, forget gameart, even WHEN you're doing gameart. Everything benefits from this. Selout was a flawed conception to begin with and only works for stuff that is highly specialized for it, and your stuff just gets added dirt because of it. Lightness should apply to outlines, even when they're differentiating signifiers (meaning: when the are ment to say 'HERE the arm ends, and the jacket begins') and the trick is to make them dark ENOUGH, not a collection of dots impressing a broken dirty outline.
the sounds all 'I ARES KNOWE THE TRUETH' but I don't mean it as such, I am just in a hurry. This is all IMO and you can take it or leave it. Just trying to help.