After seeing the set picture leak it got me thinking, what if the engineers we met in Prometheus were actually just another seeded life form (like us) but further along in development.
It fits in with the theme of stealing from the Gods - what if they stole the technology and ability to create life from their own creators - then started messing around with it.
It would go some way to explain:
•The fact they managed to mess up and wipe themselves out (i.e. they didn't know what they were doing)
•The murals of other lifeforms and the shrine image of the Xeno i.e. there is something they seem to regard as higher than themselves, or are striving to achieve
•Their desire to wipe out humans and potentially the other race we have seen in the leaked set photos i.e. wipe out the competition / destroy God's other works as revenge
Further support for this theory is the DNA match in Prometheus, they are an exact DNA match to humans.
The main thing against this theory is the scene at the start of Prometheus - however if we look at this as the engineer trying to use the planet seeding they have stolen, it kind of works and is nicely symbolic i.e. using the fire destroys them
Things that still make no sense:
•The directions to that planet left on Earth (possibly Engineers saying, come visit us once you are useful)
•The reason the engineer is not happy about David being a robot (perhaps in the act of creating "life" humans mimic God which really pissed him off)
The main thing I like about this is that it changes the Engineers from antagonists to something else.
Thoughts?