The biggest difficulty for Prometheus in being treated on its own merits is that, if its goal was to attempt the same structure as Alien, the only way it could ever properly step out of the originals shadow would be by doing a better job at being a slow-burn survivalist horror. The characters would need to resonate more deeply, the plot even more engaging, and the set pieces even more nerve-shredding and emotive. If, however, Prometheus was going to tell a completely different story or even to completely change the style, it is most likely that there would have been fewer comparisons between the two, and this debate would have been a lot less prominent in audience reactions. Aliens is such a highly-regarded sequel because it turned the concept on its head, working from a very similar starting concept, but in a very different way. It gave us an Alien action film, with entertaining, quip-handy characters, much larger set pieces and as much use of excitement as dread. It was much easier to look at the two as separate beasts because they dont, at least superficially, look that much alike. In the first hour or so, Prometheus does not feel particularly indebted to Alien at all, and it makes the film soar. The ideas are big and important, the characters feel motivated and (relatively) realistic, and it feels open and detailed, neatly contrasting with the cramped, claustrophobic feel of the Nostromo in the original. It feels as though the film will in fact be a more detailed look at creation, our relationship with our origins, and how we deal with them on a personal level, but without forgetting to be entertaining and emotional at the same time. It treats its theme and characters as important, if not more so, than its spectacle.
Roughly about the stage when Fifield and Milburn are attacked in the head chamber, the film begins to jettison the thematic and character questions, and focus almost exclusively on set pieces and plot movement. Its completely reductive to suggest that the film could not have balanced both its ambitious theme and an exhilarating plot, but for all of the motivation and set up in its first half, there is little pay off to these moments or the arcs of the characters themselves in its third act. Whether intentional or not, it provides the unfortunate effect of making the second half feel like a survivalist horror, which retroactively makes the depth of the first half feel like its slow-burn build up. Knocking off characters to ramp up the danger at the expense of their development (spare a thought for poor Vickers), and leaning on the emotion of the audience at the expense of its cerebral elements pulls Prometheus into a comparison with Alien, which is unfortunate but ultimately inevitable. By the end of the film, they look similar enough to each other to draw these comparisons. Compounding this is that, for all of the talk of there being little DNA between them, the film both goes out of its way to establish connections and also unintentionally walks into common ground between them. While Michael Fassbenders David is both brilliantly-played and a fascinating character, his fate resembles that of previous androids, Ash and Bishop, a little too closely. The design of the temple is incredible, but the references to the xenomorph on the walls and the rows of containers in the head chamber recall the first film so much that it is difficult not to make the connection. And the facehugger-styled creatures, both the snake monster that rams itself down Milburns throat and the giant beast that assaults the Space Jockey, continue this theme not to mention the tacked on appearance of the alien creature bursting forth at the very end of the film. http://www.youtube.com/watch?v=cZlDvGex3sc (a comparison of the Alien and Prometheus trailers) The only other option Prometheus had to avoid these comparisons would have been to consciously drop the xenomorph entirely, and not attempt a survivalist horror. It could have taken the Space Jockeys as a jumping off point and never had any more reference to the original franchise. However, the film was pre-loaded with expectations of it being a continuation rather than something standalone, and the film's marketing, particularly in styling Prometheus' trailer in the same way as that of the original, is proof that the studio had no intention of letting Prometheus exist entirely on its own merits. Prometheus is a stunning film, and to see a summer blockbuster raise the questions it does is a fantastic step forwards in the development of big films being unafraid to make you think, as well as make you feel. The first hour at least is one of the boldest, most intriguing in sci-fi of recent years, and there are many elements of the second half that remain impressive. But if you find yourself unable to shake the feeling that it owes more than it should to Alien that does not make you an idiot.