Lol, I was about to ask if that was a model of gumi, but Steampianist asked it already, so now I know.
I was also going to ask what engine you used to animate this (I had assumed it was mmd), but you answered it in the description!
Like others have said, the recoil on the guns should have been better (instead of just rotating just the wrists, you should have rotated the arms (individually for each joint, of course). Other than that, it's really good. Keep up the fantastic work!