Prometheus adds an entire new dimension to the setting, the existential/spiritual/philosophical side, a quest for origins, meaning and destiny, and with that it enlarges the scale with stunning grandiose music and panoramic, it is almost the opposite of the first Alien movie in this regard, rather than claustrophobia, everything is big, too big for the human being, it is an entire different approach to cosmic horror putting the emphasis on how everything in this universe is at a larger scale than us, a scale we cannot hope to truly comprehend.
And then it crashes this magnitude and magnificence against the (usual for this series) body horror, putting humans back in their place as
meat, biomass only fit to be
used in larger processes by more powerful entities. It is an absolutely sinister and cynical answer to existential inquiries which possesses its own kind of morbid beauty.
Prometheus also proposes a movie almost entirely devoid of the emblematic Alien monster. The 1979 nightmare is only present through echoes, most of them being peripheral and of no consequence to the main plot and action. You could remove the Fifield abomination and the Deacon particularly without changing the story structure... and Damon & Ridley probably
should have, for these superfluous elements are one of the main aesthetical and narrative weaknesses of the work(along with the well-know plotholes).
It's a brave move to choose to NOT rely on the Alien, and given previous exchanges (
"The Alien is cooked",
"the problem is that every single movie in this franchise features them, in the exact same way", you already know, SiL, that it's one I entirely welcome, and that it's one I even think necessary for the franchise to develop.
Additionally, the movie takes a few radical positions that people will hate or love, such as the Space Jockey fossil in Alien being retconned into a biomechanical spacesuit for human-like extraterrestrial, superhuman creatures who seed the cosmos with life (tying back to the "ancient astronauts" conspiracy theory and to a lot of popular UFO mythology), the Derelict ship being retconned into a bomber loaded with bioweapons, or a "black liquid" (inspired by the black oil in X-Files?), a mutagenic substance turning lifeforms into contagious, predatory abominations.
Personally I'm not entirely happy with these positions, for various reasons - I like the Engineer design but I dislike abandoning the elephantine profile, I think it's a mistake to
explain all of the remaining mysteries of Alien, etc - but they are
risk takings. They sweep over decades of extended universe works and fanon imagination and impose new facts upon what we thought we knew.
Despite its imperfections, Prometheus is a complete and bold new proposition.