@xeno_alpha_07, from 1: 10 of the following video:
Take a look and you will see a scene that appears to show the Elder Engineer talking with the sacrifice Engineer.
Also (in the same video) there is another version of the mutant Fifield rising, but not as the version that appears in the extras section...
but rather as in this photo:
And a little more about last engineer:
And what appears to be unused viral marketing, showing Weyland at its colony on Mars:
There is also a scene showing small spheres leaving the interior of the Prometheus, while the ship is in the space. Is this fan made? or authentic?