So how do these gigantic plot points link back into Alien. First of all, Shaw’s baby further transforms into something which resembles an oversized face-hugger which then latches itself onto the face of the last surviving Engineer of LV-223; in the film’s closing moments a xenomorph-like creature spills out of the Engineer’s abdomen. This suggests that later down the line of evolution we will get the incredible, perfect killing machine we see throughout the Alien franchise.
It also goes someway to explain what the function of the Space Jockey is in the first Alien. In that film, Kane, Dallas and Lambert board a strange ship and find him, as well as the eggs, this is exactly the same vehicle we see in Prometheus and have seen all the way through the marketing campaign. Of course the crash landing we’ve witnessed throughout the trailers was assumed to explain the crashed ship in Alien, but it isn’t the case. Alien is set on LV-426, not LV-223 like it is here.
My theory is that on one of the other 4 planets, there are more Engineers who go back to LV-223 and discover the xenomorph which has hatched from the body of one of their fallen brothers. They then develop and refine this killing machine further to create another (failed) attack on Earth. But the machines they created were too perfect and turn violent against them, hence the hole in the chest of the Space Jockey on LV-426.
Ridley Scott has said that there are two more films to go which follow Prometheus before we fully link back to Alien. At the end, Shaw and David fly away on another abandoned craft to search for the planet where the Engineers come from, hoping to learn why the human race is intended for destruction.
We must wait to hear of this weekend’s box office grosses to see if we’ll actually see more from the Prometheus universe to completely mould with the Alien one. If it all works out, though, it could turn out to be the most highly developed and intricate film universe that we’ve seen in some time.