Some Critique, Please.

[Vipershark]

Just wondering, how come there has to be less shades? I'm removing some at the moment, but I'm just wondering.

Aside from making the sprite a lot harder to make in general, your contrast is so low that you can't see about half of those shades anyway. They're so close together in brightness (well, darkness in this case, ahaha) that your eye naturally blends them together into a single shade. In other words, you can't tell the difference between the shades, so there's no need in having the difference in the first place. Because of that, you optimize your color count and make those two shades a single shade.

For example, the bear's eyes are actually green, but the green is so dark that it looks black. You can't tell that the eyes are green at a 1px scale and I could only tell that both after zooming in and artificially making the colors brighter in Photoshop.

When the sprite is actually animated and moving this effect is only amplified because at 60 fps you're not gonna see a miniscule difference between shades when each pose is only on screen for 1/60th of a second.

In other words, you're making more work for yourself for no reason since nobody can see what you're doing anyway.

Higher contrast makes your sprite stand out and makes the features easier to see, while low contrast makes your sprites look dull and uninteresting.