These are really neat. They really buff the HUD weapons very nicely and help them match the much more hi-res view possible in modern ports.
Unfortunately, my go-to weapon (the single shotgun) is possibly the one that still needs the most buffing IMO. Generally, it just doesn't seem to be as well defined as, say, the SSG. The whole rear end looks a little indistinct, in places it looks kind of "melted" into the hands, the rear kind of curves to the left at the bottom (where the right does not) and there is even a little bit of transparency on the left rear sight that can be seen in game.
I'm not knocking the effort; it's impressive so far. I'm just pointing out something that I hope can be addressed as and when you get a chance to do it.
The red switch is visible through the gun.
The areas that struck me as needing most attention.
(Plus the back section generally - I know it's not great on the original sprite either.)
This is already the most accurate project for high-resolution sprites! 
