David's fondness for music from the Wagnerian opera Das Rheingold stands out because as of this movie, some parallels between the Alien franchise and The Ring of the Nibelung can be noticed:
Like Alberich the dwarf, David forsakes love in order to forge the ultimate weapon. Alberich did it to steal and forge the Rheingold into the eponymous Ring, while David did it to use the secrets of Engineers to create the Xenomorphs.
Like the Ring forged and cursed by Alberich, the Xenomorphs, David's ultimate creation, would bring nothing but death and ruin upon all those who sought to take them for their own and use them as the ultimate weapon. Even after David, like Alberich, is long out of the picture.
Weyland/Yutani's obsessive and narrow minded pursuit of the Xenomorphs parallels the greedy pursuit by numerous characters in the Ring Cycle to obtain the Ring.
David might see Daniels as a replacement for Shaw, even before he forcefully kisses her; the two women are physically similar and have recently lost their lovers, yet persevered against numerous odds. David even suggests that Walter is in love with Daniels, to Walter's bemusement - possibly projecting his own experiences with Shaw onto the pair.
Also, when David puts Shaw into cryo-sleep in the prologue video "The Crossing," he gently says "Sleep tight." When he does the same to Daniels, he snarks "Don't let the bed bugs bite."
If David supposedly grew to genuinely care for Shaw, why kill her? The answer is found all the way back in Prometheus and David's obsession with Lawrence of Arabia - "The trick, William Potter, is not minding that it hurts."
David also considers humans to be inferior and doomed. which would also include Shaw, no matter how much he cared for her. But it could be seen as a twisted form of affection that he used her DNA and the mutagen created creatures to spawn his perfect organisms.
This also explains his unusual incorrect sourcing of the Ozymandias quote; at this point, David simply doesn't care, other than how the meaning of it all relates to him.
Given that David created the Xenomorphs, it makes a lot more sense that Weyland-Yutani is so obsessed with acquiring the Xenomorphs for themselves in the subsequent films, since they were technically created by a product of the company's own technology.
Not necessarily so much that - Given I don't know how Weyland-Yutani can learn David is the creator of the Xenomorph, but Fridge Brilliancedefinitely comes into play with the fact that they're a creature specifically designed to destroy humankind, and we seemingly readily embrace that as something to exploit and use.
Actually, an epilogue video included as an extra on the Alien Covenant Bluray depicts David sending a coded message to Weyland-Yutani, identifying himself and talking out his motives and plans to the company, including sending them detailed files about all his genetic research.
David, true to his namesake, killed the giants!
Probably after this incident about a missing ship and its passengers, the Colonial Marines were formed or at least decided to take procedures to prevent another repeat.
In Prometheus, David showed almost no sympathy or concern for Shaw when her pregnancy was discovered. His main interest was in the fetus, and he was willing to force her to stay pregnant (admittedly in cryo) so that he could keep the fetus and study it. It foreshadows her eventual fate at his hands, and that no matter his feelings for her, David will place his own scientific interests over Shaw's well-being.
The Covenant crew having no protection from the atmosphere on an alien planet is pure idiocy, right? Not necessarily. There's a very simple reason they could feel reasonably safe: No Biochemical Barriers. As that page points out, it's unlikely things form different world would be compatible. If humanity has explored a few habitable planets already, and are aware this trope is not in effect in this 'Verse, then the colonists have no reason to fear contamination once they've ruled out actual toxins. In turn, it makes the Black Goo and the xenomorphs scarier. . . they're the only things in the universe that play the trope straight.
One character, Lope, is attacked by a facehugger but, despite injuring him in the process, his partner almost immediately manages to forcibly remove it, and the facehugger dies after apparently failing. Lope is still infected with and killed by an alien embryo, which is a Cerebus Retcon for every character in the series who was ever attacked by one, as it means they infected instantaneously and the chances of saving them were slimmer than even the audience ever thought. The facehugger then must plant the egg in a split second and only "hugs" the victim for hours afterward in order to keep the victim unconscious so they are less likely to die or try and remove the alien before it bursts out.
Possible explanation could be that the Facehugger implants an embryo immediately if it senses imminent removal or death?
It's highly unlikely that the parasite normally implants the "embryo" or viral agent immediately upon attachment, however, the above is correct in that the facehugger will remain attached to ensure that the implant is secure and starts developing in the chest cavity. Basically sources say that while a facehugger stays attached to a host for up to 26 hours, implantation occurs just below half that time as the Weyland-Yutani report states that they will remain attached post implantation for up to 16 hours. Still, the incident is hard to reconcile as it is absurdly fast and makes the creature's abilty to keep a host alive mostly redundant if it can just infect instantly, another point to consider is that these are not the Xenomorph types we know, they are David's version.
It's also possible that David implanted Lope when he was dressing the burn on his cheek, using spores or something. He did have a couple of embryos on his person, after all. There was no need for the scene of "Walter" dressing his wound otherwise; the film didn't really need three scenes of a man getting a bandage applied to his face. He could've indeed escaped the facehugger only to be implanted anyway.
One character claims how it's strange that the world is completely quiet, no birds or anything. When we get to David's study we see why: Every last animal on the planet was killed off by the xenomorphs or David infecting them with his virus to create a new one.
This film gives us a glimpse into a sort of missing link between the original bioweapon and the fully developed Xenomorph with the inclusion of Neomorphs. The Neomorphs are already lightning fast, incredibly resilient, aggressive, and persistent. That wasn't good enough for David. He still went above and beyond to create a killing machine that was all of those qualities taken Up to Eleven. Really brings home just how awful these things truly are.
Dr. Elizabeth Shaw got her wish. She's effectively the mother of David's "children". She created life.
During the final fight with Xenomorph, Walter anxiously watches the screen as he cannot do anything to help Tennessee and Daniels at the time. When the alien is dead and disposed of, he lets out a visible sigh of relief, that his last two human companions are alright and the threat is disposed of. Until the story is finished and you know it is not Walter, but David. And therefore it is more a sigh of disappointment/mourning for the dead Xeno that failed to prove that it is a perfect killer.