Disappointing, full of bad science, unexplained events and plot holes

Rating: 5/10 (8 July 2012)

As expected from Ridley Scott, the visual effects and sets are stunning. Unfortunately, this doesn't save Prometheus from being uncomfortably close to bad.
The science in the movie, and the actions of the "scientists" are terrible. As others have noted, here they are on a planet where human life supposedly originated, so there is a strong biological similarity and risk of contamination, infection and disease, and within five minutes they're (including the "biologist") taking their masks off and breathing the air in a dark, wet cave? Finding a possibly hostile organism and not avoiding it? Touching random brown goo without worrying about what it is? Ridiculous, contrived and it stretched believability beyond the breaking point.
A couple of things that I haven't seen mentioned yet: The "biologist" states that the idea that these beings created us would throw out three hundred years of "Darwinism". This term is used by creationists to make evolutionary biology sound like a religion or philosophy rather than a hard science with millions of pieces of evidence behind it. While it's slipped into popular lingo and used by those who might not know otherwise, a biologist would be unlikely to use it. It's evolutionary biology, thanks.
Vickers, Charlize Theron's character, appears to be second-in-command of the ship and thus intimately familiar with the distances involved. Yet she asks the captain why she would join the mission to get "half a billion miles" from the men of Earth. At the beginning of the movie it's indicated that their distance from Earth is in the 10^14 km magnitude (maybe 50 to 100 light years from Earth.) So, she was only off by a factor of two to four hundred thousand times. (Coincidentally, or not, this is about how far creationists are off from the age of the Earth/universe.) The science consultant must have fallen asleep during the readings. I don't blame him/her as I nodded off once myself, and my wife twice.
You can attempt to rationalize some of these (such as the carbon dating device working in an alien environment where the long-term C14/12 ratio is unknown) by claiming that hey, it's future technology, but the errors above and others tell me that they were simply mistakes.
Nothing is explained properly. There's no explanation how we could be "created" by something extraterrestrial yet still demonstrably related to everything else on Earth. It's never explained why, or even if, the parent race wanted to wipe us out. It's certainly not explained how the crew suddenly knew that this is what they intended, with enough certainly to commit suicide to stop them, or why that last surviving "Engineer" was asleep waiting for them to find and awaken him (and possibly stop him) rather than just going and doing it! The story is a muddled mess full of plot holes.
I'll give it a 5 for the effects and the sets, and Michael Fassbender's performance was excellent, but there's nothing else redeeming in this film.