Well, basically all of that stuff highlighted in red is WAY too detailed. You just need simple geometry plus a texture to make the same general effect. Also, the body looks pretty dense in geometry as well. And yeah, I meant to restart from scratch. Unless you can salvage this model down to a much lower polycount
Also, I suggest that you crop your images so that there isn't a sea of black space. And it's usually better to render your models on a neutral background.