his legs need to bend more, right now everything below his knee shrinks when he steps up

If I were making this into a game, I would go with as few colors as possible. I liked it in Arnes pallette because there was a simple shading line that brought out the character, so that he would appear on different colored backgrounds. But like I said before, fewer colors the better because you will have to end up animating these things. Though you could get away with 3 frame animations if you tried hard... But whatever... Personally, I do not like the shiny rendering, makes the character less fluffy and more metallic; plus it gives him less character.

Aye damn... ok, well I'll go into detail. its a top down shooter and this particular sprite is a tank, but not your traditional tank. Hell, lets call it a vehicle. It has no turret, it is facing to the right. And at the moment it doesnt feel quite finished to me, render wise. The lineart feels fine however.

I would consider adding some tiles that break the grid look. Try adding indentations in the grass or some hills or something. Perhaps multiple cliff sides? Some rocks and other objects would add some well deserved variation.