David did not kill Engineers

Ok, but Scott said they are Engineers...

Wouldn't be the first time he flip flopped after a movie release to confuse the fanbase. Their body size, skin refractivity, eyes and behavior simply to not add up. They are the same size as the crew when they walk past.

So the superior engineer master race who are atleast 4 BILLION years ahead of humanity (their creation, lol) in terms of evolution and scientific knowhow (4 BILLION,... not a thousand years ahead but 4 billion, a third of the age of the entire UNIVERSE lol), gets wiped out by a single robot.

It's ridiculous. Like a childrens cartoon.

The engineers were the whole mystery of Prometheus. 

If that is so A:C sucked even more than most people think. 

It's just one planet. Possibly a hidden one...

I'm sure there are more Engineers in the Galaxy, and they'll have a significant role in the next Alien movie.

As I mentioned in another thread. I believe these humanoids are the Engineers prized possesion. From time to time they come in and do whatever is they do and leave. Just like with humans milennia ago. It seems humans were targeted for destruction for some unknown reason. This would explain why this planet is hidden as the Engineers did not want anyone to find their prized possession. Thats why these humanoids have all these buldings dedicated to them I suppose.

Then again, it seems the Engineers are extinct or something as no one else continued their mission for 2k years. 

OP makes some good points.  Yes, the residents of that planet do appear to be plebs as compared to The Engineers in Prometheus.  They appear to be markedly different.  I think that Sir Ridley had created them with a story arc in mind that diverged slightly from The Engineers.  I can't help but wonder if this was something that planned, fleshed out, and partially filmed... but then the story arc was abandoned, then repurposed into the scene that made it into theaters.  If there is only one more movie planned, I doubt that much of this will be revisited, or if any answers will be forthcoming.

Was also highly dissapointed by the fact this could be the Engineers and are killed like sheep when they gather beneath the Juggernaut.

Idk. Hard to say what RS really intends them to be, even after his recent interview.

I seem them as the Engineers most successful experiment (like they tried with humanity till 2k years ago).

This may explain their slightly different look (different than humans but leans towards their creators with the pale skin,form of the nose,bald head) and apparent possession of alien high tech (even if very little of it).

That local lifeform on Planet 4 looks like it's in a long planned preperation phase to be a worthy creation and possibly even maybe integrated into their whole society when they reach a certain evolution state and technology wise state.

That they have only one town and one huge docking station is maybe intended at this state of their development state.

Engineers are not dead. David created the xeno eggs yes? So explain how loads got onto a juggernaut and managed to kill the engineer aka space jockey? The timing would not add up unless engineers are still alive. So Ridley has screwed himself there if he claims the engineers are all dead. 

I think the engineers on planet 4 are a creation of the engineers in their own "ancient egypt" time period. They probably used a hieroglyphic writing system and the only tech they had was the scorpion mothership (for whatever reason it was there and stays there).