The black outer glow is done badly. It gets cut off at the top, bottom and sides of the gun so it makes the weapons look blocky. All you need to do is just give every weapon and extra edge of pixels and extend the glow into them so it looks smooth, although with the intensity of your glow, you may need an extra 2 pixels to each edge.
Other than that great work though i do find the mp5 grip sorta misshaped. Too straight and fat.
