Some Critique, Please.

[Vipershark]

To be completely honest with you, when I look at these I think the one on the right with less colors looks better due to the higher contrast between the shades. Especially on the hoodie. The left one gets so dark that much of the detail seems to get lost because you can't make out the differences between shades as well. In motion, you wouldn't be able to see it at all.
Like I said, I didn't do any hue shifting and I didn't put all the shading back or anything so it can look a lot better than it does. I just pulled the colors straight from your own palette.

Though I think it's unnecessary, if you're adamant about using more than 7 colors then I think you should try going for 10 plus transparency instead.

That's three shades for the green, blue, and black for nine colors, plus the black outline to make 10.
For this sprite in particular, you really should never need more than that since your colors are close enough that you can do easy hue shifting.
I might even cut that to 9 plus transparency if I were you since there's no need for the hoodie to be that dark. You can remove a shade there.

Especially considering that the top three colors in your palette (and the second row, 3rd column) are so dark that they all look like the exact same color.