There are two things that I would like to see, one is some better integration with the background by the feet sinking in to the dirt a bit, maybe some tracks or scuffmarks. And two is the barely imperceptible difference in resolution between the background and the mech. Maybe filter that.
there are no uvs for this model yet.. im texturing from camera angle ontop of the model in photoshop then reprojecting the textures from the camera onto the model to put the textures back onto the model
i thought this was a photograph of painted plastic model.
i think what causes the effect is that the perfectly clean edges, smooth reflections and smooth shadows, conflict with the dusty "battle worn" texture. It's jarring, so it gives the impression someone has just taken a fresh model and painted the effect onto it. You can still tell it's got unreal perfectly crisp edges and surfaces underneath that texture.
TL;DR: Needs moar bumps maybe? Particularly on the sharp edges (that's where the metal is most vulnerable to dings). eg: the reflections & shadows on those knee-cap ridges are way too crisp. Or maybe i'm expecting sand/dust to be piled up in certain areas, or maybe it's the lack of focus, urgh i wish i knew exactly what it was that was jarring me about it. Sorry for the crit if it wasn't wanted, just trying to help with my admittedly amateur eyes (so pay no mind if i'm speaking out my ass).
These are valid points!,.. funny you should mention actually!.. because ive just started to set up a new render in a new environment in an awesome action pose!.. I'll be working harder to get more valid detail in the image to hopefully achieve a more realistic result. its been over a year since I created this image, so ive learnt allot since then and hopfuly it will show in the next image .. stay tuned