Thing is. We are dealing with religion and creation in this movie... and for some reason... there is just no reaction to either of those topics within the movie, except for the references to Shaw's father's cross and David insinuating that her wanting the cross means she believes. It just doesn't indicate that. That just isn't the only reason she would want and wear that cross... so the conclusion David makes is faulty.
There is just no drama regarding what they find - and the first scene in the movie sorta kills all the mystery about it, so it just becomes such a bland, almost numb experience they are going through, because we already have the answer even before we go on the journey, which means... what the hell is the whole movie's point? It's like learning the big mystery at the end of a story right up front... then you don't really feel any suspense or interest in all the hoops they have to jump and corners they have to turn to get to the answer at the end... you just feel bored. Sure... it could be made interesting through the character interactions and playing various beliefs and theories up against each other, but there is just none of that at all... it's like... nothing really matters about the questions raised and the answers they do find or the answers they don't. There's just no drive for any of the characters to really be there or strive to, no real drama and sadly... no mystery.
In all honesty... it would have been better if the first scene was removed, the head was found a lot later in the story - or at least generated some debate or frustrations, doubts, fears, even anger between the characters and hearing some theories - and the reveal of the space jockey only seen towards the end, with him taking the mask off there, instead of seeing them so many times earlier. Make the fact that they have human looking faces a surprise and mystery.
I don't know. I was rather looking forward to seeing some of the ideas brought to screen that Ridley Scott talked about on the commentaries on Alien and in interviews. Sure... it's there, but it just feel like such a pointless movie, and I really find that to be a shame. In all honesty... it just feels like it's too short, too cramped, too much happening too soon, and the emphasis was laid on the visuals rather than on the characters and their reactions to what they were seeing and learning.