Well all we can say is this movie has some colossal screw ups compared to the ideas and concepts and ideas from the scripts.....
The main disappointments for me was the lack of scale and also the contradictions, the movie in places just lacked coherent flow... and had many things going on with little connection well contradiction, i.e there was clues to a number of possible things going on and this is all Lindelofs style of Ambiguity he uses in Lost..
First of all lets look at the Chest Busted Engineers, as yes this image posted proves they was going for Chest Busted Engineers at the actual filming of the movie, and not just Script. Now the detail on the Engineer is lacking and has no feet lol, but its not needed as these Engineers will never been seen in detail ones the Cryo Pod lid is on and its broken glass, you will not clearly see the Engineers under it.
But this image does show they are indeed Chest Busted, which being as though this movie is in the Alien Franchise we can all safely assume means they was chest busted via some Organism related to the Xeno or the Deacon.
This adds a possibility to what could be chasing the Engineers, it could also mean some of the holes in the dead Engineers are puncture wounds caused by said Organisms....
But then we are left with a puzzle, that is why did the movie lead a lot of emphasis on an infection, and also the exploding head to send us down the route that maybe these Engineers suffered the same fate....
Yet we are also left with the what appeared to be Chest Busted Cryo Pods and that scream... that was like the Deacons....
While Lindeloff can pass this off as keeping the movie ambiguous and leaving us with no clear answer and only clues that can lead to more than one outcome... sometimes while i am a fan of ambiguity... (The Murals etc are Ambiguous) some things are just plain contradicting.
As it is now we can only guess that both a outbreak and a Chest Busting had occurred in what order who knows, and how the Last Engineer survived again, who knows...
Second onto the subject of Scale, this is my biggest gripe with the movie... and Ridley and Fox dropped a Bo Bo in Alien as well...
You see the idea was our Space Jockey was 26ft, and that by using a 16ft chair with a Space Jockey Prop and what up to 4ft tall Child Actors we would get the grand scale of a huge being, well the illusion would been 22-23ft tall not 26ft
When they switched to proper Adult actors up close we could see our Space Jockey was 15ft tops, and i recon he was about 13ft.
Switch to Prometheus the Drafts all went the way to show a 12-15ft race that coincide with the size of the Space Jockey, when they filmed the movie they could not get that sense of scale so revised the size and tried to create the Illusion of a 9-10ft tall Race of Engineers...
Sadly again this failed and all we was left with was 8ft Tops illusion...
In fact looking at the Chest Busted Engineer in that Cryo Pod we can clearly see those pods would never hold a 9ft being and the one lying dead is what 6.5ft Tops