Have the same opinion about all wolf said with his advice.
however I'd say that your many colors rather cause readability issues, since you soften shapes which shouldn't be softened and so you rather produce a gradient in a lot of spots there there than the form detail you intended to achieve.
Means if the contrast is to low colors are blurring together. Visually seen that's currently your biggest issue art wise.
If the contrast is to high, it gets to busy for the eye and you can't grasp the overall appaerance.
If the contrast is right as in wolf's edit colors will blend where they should (round helmet) and provide clear details were needed (face details)
To bring out form on such a tiny sprite you need a good seperation of planes and a good choice for colors, where they blend and where they contrast.
Wolf's orc looks really readable now but has 2 big things why it don't goes along well with what you want to achieve and still looks kinda "flat" if you put it on the background.
1)In terms of perspective it's pure sideview and therefore not in line with the game-world which has a 45° viewing angle.
Therefore wolf's sprite is not flat, but it's still not as 3d as it could be and it falls out of the world.
look at the perspectivical axis (chart, wolfs's orc, red lines).
If you look at original hammerwatch sprites you will see that they will use more colors, but more importantly you will see that every of the 8 directions has the same underlying raw base forms with cylinders where you can see the top and the front plane (check it out in the diagram - esp. the high res version for the knight).
2)Also on top of that Hammerwatch sprites tend to have quite small bodys and smaller heads.
If you want to capture the style effectively the head/body proportions should be somewhat similar.
side note: To ground the sprite you also can give the feet a sense of connection to the ground and a perspectivical appearance, which will anchor the sprite in the game world.
So I kept all changes Wolf made and just added these 3 thoughts on top of it which adress completely different points.
