Prometheus Vs Aliens

There's beauty in simplicity, and the Aliens franchise is no different. I've been thinking about just why Prometheus fell apart while the rest of the franchise managed to largely hold together, however simple and possibly shallow the whole xenomorph thing was. The original premise was that the xenomorphs were an apparently biomechanoid hive creatures that reproduced by parasiting other species. Prometheus attempts to expand upon this mythology, with very little success. Just what went wrong? If we were to consider the original Alien, it was fairly clear that the xenomorph gained biomass by infecting hosts and growing. In the later movies, the reveal of the Queen simply helped to flesh out the rest of the xenomorph life cycle. When Prometheus tried to explain the origin of the xenomorph and how it related to humans, the attempt was a tad convoluted and lost plausibility as a result. The flow seems to be as follows: The xenomorph began as a microbial goop bioweapon. If it infects a Jockey, it either causes spontaneous disintegration at the DNA level, or causes the Jockey's head to explode. The goop itself transforms regular worms into a serpentine facehugger. This serpentine facehugger apparently burrows down a human gullet to zombiefy it. Doesn't appear to do anything else. If the xenomicrobe were to infect a human, the human can mate with another human to impregnate the female with a squidlike facehugger. The human apparently dies after this, outcome unknown. This facehugger spontaneously gains biomass (????) and can implant itself in the Jockey race in order to create the first true xenomorph queen. Now, such a convoluted series of combinations does little to help with the xenomorph mythos simply because each stage raises fresh questions. It would probably have been more elegant to line the life stages up, whereby the goop infests a worm, which turns into a serpent which infests a human and becomes a facehugger which eventually infects a Jockey and forms the first xenomorph queen. With the various branches presented in the movie, questions are raised like: What, exactly does the zombie human do? Why did the infested Jockey's head explode when reanimated, yet causes the other Jockey to disintegrate when imbibed? Where did the squid xenomorph get its biomass, and why is that biomass required in the first place? Finally, if the Jockeys knew that the xenomorph goop was exceedingly dangerous (nearly resulting in the extinction of a species that's apparently biologically identical to humans), why did they insist on bringing the goop to earth to eliminate the other humans? Ultimately, the attempt at creating a more diversified application for the original xenomorph bioweapon opened a can of worms (pun intended) and really doesn't help in clarifying premise of the series. At this point, I'll also contribute my weird interpretation of the thing: The "Engineers" or "Space Jockeys" are basically Space Marines, from Warhammer 40k. We know this from the great height and strength, and the black carapace on the humanoid's torso. Clearly an unarmored and unarmed Astartes. What you find in the canopic jars are really virus bomb goop. We know this because it causes a horrible reek (emission of flammable gases) in an infected human, followed by spontaneous explosion of the head. It disintegrates biomass (Jockey disintegration), presumably releasing the same gases. At some point, all biomass on the planet will decay, causing the atmosphere to be filled with flammable gases, facilitating exterminatus. The last surviving Space Marine simply wished to launch the shuttle to Terra in order to complete the virus bombing, but failed. Of course, credit must be given where due, and I think Prometheus had some fine attention to visual detail. All the facehugger prototypes had some aspect of its vagino-phallic reproductive organ. The Space Jockey seat was very clearly explained, and the way the pilot fit in that strange humanoid sculpture explained just why there was a humanoid aboard a xenomorph ship, and just how the xenomorphs are associated with humans. I actually did spend most of the movie oogling the details and seeing how they try to fit in with the original Alien series.