This is more Pixel Art than a Sprite. (Even though it was never said to be a sprite in the first place.)
It looks very interesting, the right hand looks extremely weird like that though.
Few other things: his left arm is also missing, and the anatomy is unclear, mostly around the area where that left arm should be.
The palette needed more contrast and variety. Used Ryumaru's avatar's palette as reference, as it turns out those colors are actually pretty similar. Try shifting to warmer/cooler colors on lighter/darker colors of a palette, which is known as hue-shifting.
By the way when determining the lightsource try to keep light areas separated from dark areas. For example, in the edit below, the left forearm is darker than the right forearm, with no immediate speculars on it (other than the secondary light you see there). The other arm has more light cast onto it and more speculars, which separates it from the rest of the figure and keeps things readable. (edit: improved on this) As for anatomy, legs look odd below the knees, may expand upon this edit and get to that later. There's a few tips on arm anatomy by Arne
here as well.
An afterthought: right arm still seems a bit short/flat, underlying forms there could probably be improved.
HTH.
