It's a fabulous idea! I love how your implemented slave arms with the master arms as well as being slightly more robotic than human or perhaps a hybrid of some sorts? I also like how you gave this bipedal machine a Predator equipped shoulder gun on the left shoulder (right facing us) and the option to add another armament or defensive piece of equipment on the right shoulder.
While I think the picture looks finished, I believe you could add more details to it's arms, legs and feet. They need a little help... all in all, this sketch of yours is far from being just shit.