Amazing! I really liked, it it had me from the first shot and the thumbing sound it did and the particles when dissipated. Really nice details, from the animation of the gun pointing everywhere and the slide, till the particles floating around when moving. If I would suggest something, like when in the air and you shoot and you gain some momentum upwards, should be in all four directions.
As a side note, I would have liked the movement controls to be on the left side, as in the handheld.