|I'm not sure I can nail exactly why, but Chris is right, the feel is more Terminator than Matrix. I think partly it's the pose. I'm not a total Matrix nut so I may be off, but I think most of the more dramatic moments in the movie have Keanu with more of a forward, downward tilt of his head, eyes looking up from under his brow, with the guns lower and/or pointing down. Arnold affects the more stand straight, head up, guns pointed upward stance.
Beyond that, on the technical side, you mentioned the composition - needs more room around the edges. And the white background needs to be whiter and cleaner - I see some wrinkles or creases and reflections and it's kinda splotchy.
And... you never answered the question in the comments: Where'd you get all those guns? Are you a collector?