I like the cat ! You should do a fox too ! And I suggest making the cat's tail visible even from the front. I find him kind of fat though, but maybe that's on purpose.

Hi! I'm making art for a game, in which there's possibly gonna be a high amount of avatar customization.
To make my work easier I've reduced the resolution of the player character at a minimum and reduced the animations to as little frames as possible.

(the sprite will be at 300 or 400% size)

I'll be happy to receive any critique on the design (and the animation). I'm also curious about the different styles there are for such small characters. So if someone wants to make an edit / do their own version of this character in another style while keeping the same size, please go ahead.

I second Eduardo on most of the things he mentioned, especially this :

I would try to avoid so much line dependency, you are using it as a crutch to separate planes.[...]Try to see the character as a 3D object.

Try not to represent volumes with lines (ex. the vertical line on her throat), but decide of a lightsource and try instead representing the way light and shadows hit those volumes. After all, that's how it works in real life. If you ever wonder, "how does light hit this particular shape?", don't hesitate to search similar objects on Google to have a reference ("face lighting"...).

I had some fun editing your piece, so I could better explain some stuff:

• First thing I did is I picked a lightsource (top-left corner) and redid the shading accordingly. Note how the camera-right half of her face is in shadows.
• Some of your shading was too radical and made some parts look a bit plastic-like, her boobs for instance! I tried to give them a more suffuse, soft shading/lighting.
• I find some of the colors "clash" together, because they have "nothing in common". In my edit I tried to harmonize the different colors (green, blue, purple, skintone...) by experimenting with hue-shifting. For instance, I shifted the darker skin color more towards a reddish/pink/purply hue so that it worked better with the purple of her hair. Hue-shifting is what's gonna make your piece more interesting to the eye. -> the palette construction you used VS the one I used: (not saying mine is better, it's just to illustrate the kind of palette construction resulting from playing with hue-shifting: the colors all share some shades)
• In terms of color count, less is more. You didn't do a bad job, but I further reduced the color count from 20 to 14, by reusing a same color for different purposes (see bandana and clothing. I also reused some skin colors for the hair reflections and the white of her eyes); in my opinion it ties a piece together by giving it coherence. The second edit is a more radical and old-school color count reduction, dropping to 12 colors.
• Her hair has potential, but as it is it kind of gives the impression of "clumps" of bubble gum. I tried to give it a "hairier" texture, with more pointy ends and more individual waves.
• Anatomically, part of her shoulders was missing, so I further defined their shape.
• Pixel art traditionally has a low resolution. Some details can get lost if they aren't clearly expressed. She's wearing a pirate-like bandana? Show that it's a bandana! Don't hide the knot part behind her head!
• This one is a matter of tastes: I tried not to rely too much on outlines, making them disappear a little in highly-lit areas (camera-left part of her silhouette), it looks less "harsh" this way imo.
  

Take all this with a grain of salt as I am no professional. I hope this helps a bit!

EDIT: I didn't see you were using a specific palette, my bad, here's my edit with the palette you're using:

Hi !
Please tell me everything that looks wrong with this idle animation :