No adjustments to lighting or shadows? Add some and it could look better. He should be a lot bigger too. He is a spartan.
Even so, you really should have added the lighting and shadows... Also, those renders are not very clean. There is a thin black line around Mater Chief and the dog has a white line around it. As Lock said, the perspective is off, because a spartan should be taller than a car, which I am pretty sure Master Chief is not at this point. For the random piece, I need to see the stock to give proper CnC.