Very nie work. Can you please uploaded in its original scale?
PixelJoint has a zoom feature that allows to check the artwork in higher scales.
If you open your image up in the site's Image Specs Tool you can see the colour table for the animation. There are a lot of colours that seem to get used for a pixel or a couple pixels, and some that only show up for a frame or two in the whole animation. I get the impression this could have been made in like, 16 or so colours, but we're looking at over 50 instead. Did you work with a smaller palette for the .gif at first, and run into issues during the export process; or did you not work with a defined palette and added colours as you went back and forth editing all the frames; or did you take another approach when building this animation?
Previews can't contain gore