So, what did you change deliberately?
Here we go:
1. Barrel has a thicker wall. I didn't have a drill big enough and the inner cutters for the lathe are too big. Also I think it looks better this way.
2. Some of the pockets on canisters have curved bottom (so they follow the curvature of the canister), I made all of the pockets on my cnc and they all have flat bottoms.
3. I added an allen screw on the back of the targeting device and a magnet on the front, thus making it removable. (side note: the big canister and the top silver canister are screwed in so they're also removable). I made the two little panels on the back of the device look like glass.
4. Some of the pockets on movie gun have sharp inner edges. I left the edges on my gun as machined on the router - with a radius.
5. This part on the movie gun is thicker than the part leading towards the trigger. You can see the step on the Weta replica. I left this out.
6. I made the slide white like on the movie gun. On the Weta replica it's black.
7. Trigger has a simpler shape.
8. The movie gun and Weta replica have black circles all over the left side (for assembling the two halves of the gun probably). I didn't like those.
9. The shape around the black radiator thingy is different. Above the radiator is an area that is black on the original and white (dirty) on my gun.
10. Part of the gun below the silver canister on the original is curved, so it closely follows the canister (no gap between the canister and the gun). This part is flat on my gun with the two wings sticking out, so there is a gap between the gun and the canisters.
11. This detail is changed a bit, the white color continues onto the chamfer a bit.