It looks nothing like pixel art to me. Just looks like a normal cel-shader...
That is what most basic pixel art looks like isn't it? Looking at your avatar it has a outline and on certain angles (cels) it gets another tint. That is what i have going on, or at least somewhat close especially the linework needs to be sharper. I will work on this if only for experiment and study sake.
Are you mixing low-poly 3D models with sprite art for your game? If all of your art assets are going to be 3D models, I honestly think you'd be better off just using normal lighting; low-poly 3D has its own charm, I think, while cel shaded stuff like this just looks sterile. Rikfuzz's edit is a step in the right direction, but it still looks somewhat cheap compared to something hand-drawn, I think.
I am making this for a 2D isometric game, i do not feel comfortable enough with programming for full blown 3D game with shaders, frustum, 3D camera, etc. So yes it probably get's mixed with 2D unless i decide to make the tiles the same way i did this one. If you look at Indigo attempt (
http://danfessler.com/work/luckyspace/) it does not look dull at all but sadly his skill level is much higher then mine

.
I'd go simple low-poly, or hand drawn. Unless you're trying to mix this turret in with other pixel art, in which case, you might have no choice. (Besides spending a lot longer making your art assets, hahah! X'D )
The model itself is nice, though. Have you tested it with some normal lighting and simple textures? You could even low-res texture it, if you're going for a retro look. Might look good!
Thanks, i have done some more complicated 3D art work, the thing is that i am not a good hand painter (i do not take the time to practice enough). Like i said i do not feel comfortable enough with 3D graphics programming so i have to go for 2D and do the artwork myself, atleast for now since 2D art for even a simple game can cost $10.000 easily. I want to do characters like this too, this way i can quickly get them quickly in a pose in 8 directions, even wearing different armor sets will be a cakewalk once i made them. I am just looking for a nice style and indigo inspired me with his work. In the end i might fall back to basic (3D) shading but not full 3D.
Maybe if it was a less complex motion, because it is rotating and tilting at the same time, which is something that seems fairly complicated for just a person to animate.
It's a box. If we want to be animators, we should be able to animate literally the simplest shape possible, no matter what it's doing. = =;;
Mind you, I can't, but I suck. There are plenty of animators out there who would have no problem with it, though. 
I might have to say that I have control over the diffuse/color map, this however is 2048 x 2048 since I am not using 3D models this does not matter for the performance of the final game. I can still add in a ton of detail but i think i want to go for a "sterile" clean look that basic pixel art has
https://www.google.nl/search?q=basic+pixel+art&es_sm=93&source=lnms&tbm=isch&sa=X&ei=xCJvU7zdL4b_PMm3gKAE&ved=0CAgQ_AUoAQ&biw=1746&bih=890. However i am still searching and experimenting for a style.
Here is the difuse sized down 2 factors.