This is great work overall! You have excellent definition of hair shapes and volume, and some great features. But I see what you mean about the middle one.

I'm aware of, but not familiar with OnePiece. However, looking around for inspiration pieces for Robin, I see what the original artists are trying to do. It's a very narrow nose with a flat front, so it has a couple of long, sharp angles.

What I noticed was that there was always a way the artists used to separate the eyebrow from the nose... corners? Let's call them corners.

Either there's a gap:




Or something that breaks up the line:



And/or a significant change in the line style.



(These are random grabs from Google Images, apologies if any are fan art or whatever.)

Another thing I noticed was the the underneath of the nose was only ever in shadow if a large chunk of the rest of the face was also in shadow.

Here's one from a similar angle to yours:



Your band of shade across the left side of the nose makes me think there's an overhang, like she has a plate stuck on the front of her nose. I would remove that, and the shadow under the nose. Then keep the dot at the base to imply the width of the nose, and add a little more shadow to the right of the nose there.

I like the hair colour and the highlights, although the detail is lost so you might be able to get away with using a lighter shade for the main bulk of the hair.

For the rest of your work, I would personally spend some time tidying up. Specifically:

 - Removing single pixels and replacing with clusters implying shape and direction. I consider single pixels to be "noise" in most cases, and where you're using them (in the pink hair for example) you probably just need to point the viewer's eyes in the right direction with a pointy cluster. In other areas you're almost dithering along a single line (left image, between clumps of hair) and it feels like you could get a better effect by sticking with one colour for solid sections of line.
 - The necks have some banding going on. I prefer to use a single shade for shadows like this, as bands of colour can start to look unnatural.
 - Removing jaggies. There are areas where I would consider some of your line work to be a bit messy still. Taking a little time to smooth off some curves, remove "corners" and generally round things off or sharpen things where they need it might help bring it alive. I'm no great artist, but if you'd like some examples of how I'd approach cleaning some things up I'd be more than happy to have a go.
 - Some of the shading around the edge of the faces is using very tight bands of a few shades. This feels a little forced to me. I think you only really need a single shade, and in some cases you can probably make the shaded area larger. (See examples above.) This is a cartoon style. You just need solid outlines and a single shade for shadows in most cases.

Apart from that, some of the anatomy feels off, but that's not my area!

Anyway, great work, I hope you find something helpful in there!

This looks pretty awesome! Excellent work. Linework and shading are on point, and I love the cartoony style.

The only potential issue I see is around the face. The dark red/brown against the black/grey outline doesn't allow me to see any detail. I'm assuming the single dot of white is supposed to be a tooth, but I had to zoom in to figure out what was going on. Also it's a single pixel, so I can only assume what it is because of its location.

I tend to try to avoid single pixels myself, but tbh I can't make characters look this good! But fwiw I'd try some face colours that stood out against the black or try using a light colour for detail. Also I'd choose a tooth colour with a bit of yellow or brown in it so it doesn't ping so much, and try to make the tooth at the very least 2px long. (Preferably wider as well, but I know you have the tiniest amount of space!)

But you know, feel free to ignore. It's a great piece imo.

A couple of things I'd try, just ideas:

 - The hair and skin are similar shades. Giving a different colour or shade to the hair might help define them better.

 - The legs both look like they're the same distance away. Make one darker to push it back.

I love this, but not for this rock. This one needs to be something that was once sculpted (or extruded?) but has fallen on hard times.

Before working on that one I was playing with this:



Which was an experiment in drawing a silhouette using a large brush, then carving it into a rock. I like it but this one IS too regular. Instead of a silhouette, your idea as a starting point could really help give it some width and interest.

And it could definitely help provide some extra scenery.

Thanks!

Well, it is a matter of taste jajaja I found it very spiky so I wanted to lower it a little, but not so much that it loses your style and details.

Thanks. There was something a little off about the angle. You helped me spot it.

Your next sample looks so much better! Using several minor cracks instead of a long one gives it the same personality but much better visually.

Thank you, but it's also true that they disappear when seen from a distance. I need to find a middle-ground I think!