Now before we get into the movie itself I have a slight bone to pick with one of the trailers I saw... starring Ben Stiller. It was called The Watch and really should have been called The Watered Down American Version of Attack the Block. You might be saying "but the plot looks completely different" sure it looks different, but at it's heart it is the same movie: an unlikely ragtag group defend their neighbourhood against an alien invasion. I wasn't really seeing a great comparison until the scenes in the trailer where they kill an alien in a warehouse (similar to the underground parking in Attack the Block) and then they goof around with the alien, posing and such. Alright, rant over, now on to Prometheus.
Also a 40% chance of spoilers with a risk of laughter follows after the break