- A lot of people wondered why the Predalien looked so radically different from the human-born aliens, whereas the dog alien from the third movie looked pretty much the same aside from some cosmetic differences. This makes sense when you consider that the DNA difference between a human and a dog would be much smaller than between a human and a life form from a completely different world.
- The dog was also considerably smaller a human or Predator host, with a narrower, shorter thoracic cavity in which to gestate, so the embryo inside the former may have had to cut short its development early, before it had acquired a complete set of species-specific traits.
- Why does the alien in the first film shake when it reaches for Brett? This is the first time it has done this in its life and reaching out for something can lead to shaking hands if it has not been done before.
- The events of Prometheus provide a plausible explanation for why Mother was able to decode some of the distress signal in Alien.
- A lot of the things that don't make sense about the Xenomorph make a lot of sense if you consider the possibility that they were designed as weapons- Hollywood Acid for blood: defense mechanism as well as the 'living battery' idea proposed in the comics. Ability to reproduce with almost any species: A perfect way of making more of them that demoralizes the enemy in the process, as well as incorporating the abilities of other species in the Xenomorph's 'design'. Taking on the characteristics of the animal they hatch from is even more sensible: that creature was already adapted to its environment, so the Xenomorph is adapted to it, as well, and adding its own advantages. And odds are the Xenomorph is taking as hosts the dominant lifeform in a given ecosystem (i.e., humans for most of the franchise), making it that much more capable.
- Might seem horrific, but a lot of Weyland-Yutani's actions are a lot more understandable if you look at it the right way. They want the aliens as bio-weapons. Seems like a fairly typical power-hunger thing that any bunch of General Rippers would do, right? Until you think about who they might need to use them on. The galaxy has just been proven to contain other intelligent, spacefaring lifeforms, or at least it did, ones vastly superior to humanity. And they're probably still around. Even if they're not, other species probably are — indeed, given the implied shared verse, the Yautja are certainly still around. Controlling the aliens provides Earth with a guaranteed-effective weapon against any aggressors. In essence, they're looking for a trump card to insure the survival of the human race. In that context, they might still be crazy, but they're more Knight Templar types than the omnicidal maniacs that they look like otherwise.
- Aliens: Colonial Marines may seem like it's Retconing things when it explains that a Chestburster gestates inside a parasitic "mock-womb" that will kill the host even if the xenomorph embryo is removed, but this actually explains something: in every continuity, we almost never see facehugged victims ever be surgically cured; surely, sheer practicality would dictate that even for a Megacorp it's more profitable to surgically extract a grown Chestburster from a victim than allow it to deliver itself in the usual lethal manner, but nobody ever does so. Even the rare benevolent "xeno-farmers" use surgical clone-lumps (non-sentient masses of clone-grown human tissue and organs) and let the Chestburster grow and remove itself from them.
- At the same time, Ripley 8 having her Chestburster surgically removed makes sense; Alien: Resurrection is set several centuries into the future of the timeline of the rest of the Alien franchise.
- Although surely not canon - the medtechs in Mega City One have little problem removing the chestbursters. https://en.wikipedia.org/wiki/Judge_Dredd_vs._Aliens
- Aliens: Defiance provides a much simpler and far more reasonable explanation for Weyland-Yutani's claim that an infected person cannot be saved. WY is simply and unambiguously lying. In that comic, a human doctor successfully manages to extract an Alien queen from her own chest cavity with no ill effects- only to be captured and murdered later by WY in an attempt to find left-over xenomorph cells inside her body cavity that they can use to clone an embryo. Telling everyone who is in a position to make demands that nothing can be done to save their friends makes it SO much easier to eliminate witnesses...
- Robots are difficult to build and expensive AF in the Alien Franchise... If Prometheus is canon, robots were already a thing some 30 years before the first Alien film. But David seems to be a novelty and works as some sort of personal assistant for millionaire Peter Weyland. Then, in Alien, Ash doesn't come across as a more advanced robot than David. Moreover, howcome humans are still necessary to man the Nostromo ship instead of just putting there a couple of robots to run the whole operation? If Ash can pass for a science officer, why not some other robot(s) as a navigator or ship engineer? Then in Aliens, again only Bishop is a robot. I can sort of understand that robots may not be trusted to function as colonial marines, but why isn't there any mention of robots as colonists? Instead of sending dozens of humans to colonize, why not send a handful of robots as an avantgarde? Centuries later, in Resurrection, Call is again the only robot in the film, not only that, but the models seem to be getting worse and worse, since by now they question orders. But the real people don't even seem to keep any Ash, David or Bishop models (Bishop being so far the only seemingly trust-worthy model in the entire franchise universe). This implies that the field of robotics is more difficult than thought, and also that robots are super-expensive despite decades of progress between the films, so much so, that they still haven't really replaced humans in menial/dangerous jobs.
- Development on androids was probably slowed due to a lot of red tape — their predecessors, the Replicants, caused a lot of problems when they rebelled and nobody wanted a repeat of the Roy Batty incident.
- How could the Xenomorphs make effective biological weapons? Their only method of killing relies on getting close to their enemies, which makes them easy to kill at a distance. Since they cluster in hives, it should also be relatively easy to bomb them from the safety of the air. Even if you were to disperse a bunch of facehuggers in a densely populated area, it would become impractical once the enemy knows what they're up against and would learn to kill anyone who's been infected after the first use. You could use something that's not a Xenomorph and that something else would likely be able to do it better.
- If you're fighting a stand-up war, sure. But Xenomorphs clearly aren't a weapon of war, they're a weapon of terror. They're designed to be as frighteningly efficient at killing as possible, and even if you can defend yourself against them, their acid blood will do a good job at damaging or destroying nearby infrastructure. They may make an easy target clustered in hives, but first you have to find the hive, and Xenomorphs are sneaky above all else. Adding all this up means that, while Xenomorphs might not win you a war, they'll certainly distract and disrupt your enemy, giving you the advantage.
- If you have quarantine procedures, and a medbay, why would those procedures not include "isolate in (specific part of) medbay, send in the android science officer to examine/operate, sterilize android after"?
- Because you contaminate everything between the airlock and the medbay just getting them there. And there's no guarantee that they'd be able to neutralise any dangerous contaminate even if they managed to restrict it to the medbay.
- Also, Ash wasn't known to be an android initially. He was a last-second replacement by the Company (because they wanted The Mole to help them get the Alien). Just keeping the potentially infected crewmember outside the ship for 24 hours while you run every decontamination protocol known to man is far more effective.