Thank you eishiya! I hope this one will be accepted.
I want to learn how to work with limited palettes because I think it would help me being more aware of what I'm doing, rather than having too many colours to chose, and getting lost at some point.
Thank you also for the edit page trick, I deleted the old Slime.
Good use of dithering here to suggest the texture that you had on the hybrid version! The form also reads more clearly on this version because there's more contrast in the colours, and the shadows have simpler shapes.
Oh yeah, in my last wall of text, I forgot to mention - limiting yourself to 16 colours isn't necessary, many great pixel works have more than that (though of course, many have less as well). If you want to teach yourself to work with very limited palettes, go for it, of couse! Or for even smaller palettes if you want! But don't feel that you have to drastically constrain yourself for your work to be pixel art.
Since your previous slime isn't likely to ever be accepted, why not replace that one with this version, instead of making a new submission?
Edit: Just realized that at present, you probably can't find the Edit button on the old one. You can still access the edit page by going to http://pixeljoint.com/pixels/submit_icons.asp?id=##### where the ##### is the ID number of your piece, which you can find in its URL. So, for your old slime, that's http://pixeljoint.com/pixels/submit_icons.asp?id=98792
Good to see a slime that isn't sporting a smile, for once.