Hi Leo,
DISCLAIMER: I'm no pixel master myself, but I hope my feedback is still valid :p
Firstly, thats a good job, I think that would look really cool in a game, a like the way the laser is done, and the shading effect when it fires really adds to the sense of "power".
BUT (yep.), it seems like there are two ways of "seeing" this sprite. Either as a tank, with the turret a little further back than the center, facing right, OR a as a a sort of robot spider puppy facing forwards (I know that sounds crazy, but without reading your description that's actually how I saw it at first :p ) Maybe you won't see it that way but I hope my confusing statement will make sense to you