I would go a step back and do thumbnails and collecting ideas with silhouettes. The current problem is that it seems (at least for me) that you dont have a clue what you actually want. For example there is a atomic sign on his shoulders but nothing on the rest of the design actually really fits with that. Also the weapon looks more like a alien made weapon from the shape and if this it's true why would have a alien a atomic sign on his suit?
Than it is pretty easy to shoot him in the upper leg because for some reason he dosen't have a protection there. Etc.
It makes for example sense to write down before you go to the silhouettes what he can actually doing gameplaywise because both of your reference are actually games and the design need to fit the gameplay of the character to present the mechanics or typ of character as good as possible for the viewer.