Hey:
Basically the main problem with this is bad color usage, along with some anatomy problems;
On the lower part of the body, you have some high contrast going on between the 2 tones used there, the lightsource is flawed in the way that the char reacts to it; you could use some integration of the colours, manage those grays and include them as highlights on the pants/legs.
Im also not too fond of the pants/shoes, youve integrated them, in a way they seem like kiddy-pajamas; give him some shoes or something like that, you have the colours to create them using the grays of the gun.
On the upper part, we have the opossite, theres not enough contrast, we have a light red thats barely noticeable up the contrast of those shades, and the same can be applied to the facial features and shadows casted.
The lightsource you have used like i said is flawed, as it doesnt seem to be casted in the same way on all the part of the char, so for instance you should definetely have a highlight on that bold head, and theres none
Im not sure of what that red and black lines on the head are supossed to be (headband?) so you might want to look into that if its a design feature.
I would also add some more logical highlights to the gun, more contrast and a variation of hues on the gray colours.
I also think that you could use some variable weight/colour outlines instead of that selout right now, as i feel its not making the piece better.
You could also apply some AA if you manage to create a good reusable shades colour pallete.
Anatomy wise, i feel that the shoulder position feels uneasy, too squarish i think. Also, acording to the perspective his left shoulder should be a little bit more towards the torso of the char.
The position of the legs/and feet seems a bit too Chaplin-esque to me, might want to look on them.
I dont understand what the left hand is supossed to be doing, or what those white things on the side are, also his right arm seem to have some unexplicable "BUMPS" on it, check that too.
If you need an edit just give a shout.
Looking forward to the progress on this, because regardless of the extensive ammount of critique i gave, i quite like this sprite, keep rocking
-Krut.
