It appears the majority of the vertex count is coming from the cylinders used to represent the joints of the robot. It seems more and more as this model progresses how important the initial cylindrical polycount is of your model (in this situation - and similar such as a cylindrical gun/wheel). The geometry has to be imitated on the smaller joints to a similar degree to not clash with the harshness of the curve from the main body.
If I were to attempt this model (or similar) in the future, during the concept stage I would be inclined to do more mesh-line sketches of the model to ensure the rotational segments would be feasible within the limited count.
I have based a lot of the degree of detail for the model of other current-gen models which are in AAA titles, I thought it'd make a lot of sense to be working on what may turn out to be higher-poly version of the vertex cap so that I may bake on normal map data to the lower-poly model later on in the process.
Below I experimented with the rigging heirarchy I setup inside 3DsMax, the hierarchy tree includes even finger tips and all the ball/rotational joints the original Bramble MK2 requires for movement. Exporting the model to Cinema 4D so I could take advantage of my more advanced rendering techniques, making the composition feel more 'alive'.
I then went forward to creating the gattling gun, fortunately there was no vertex limit for this particular accessory but I had to ensure it was of a similar degree of geometric style so not to look out of place when attached to the main model. It was also important at this stage to decide I am to use two UV maps, one for the character and one for the gun (and any other future accessories).
A similar setup to the previous DOF render, this includes the gattling gun and a slightly wider FOV to incorporate a slight curvature to the image, leading the eye from top left through the character to the focus - the hands grasping the weapon.
Below is an example turnaround of what appears to be the final geometry of the model, I rendered this 3000x1000 to ensure I could scrutinies the geometry and AO/GI of the model to see if any tweaks were required.
