[Spoilers ahead for Alien: Covenant]
Alien: Covenant is a very bad movie, and it’s bad until the credits roll. The movie is filled with dumb characters, and when the movie reaches its climax, it assumes you’re just as dumb. And instead of trying to cement the final battle and wrap up its themes (half-formed as they are), the movie gets bogged down in an obvious “Gotcha” that the audience has to suffer through so that we can see an Alien get thrown out into the vacuum of space for the umpteenth time.
As Daniels (Katherine Waterston) and Lope (Demián Bichir) struggle to meet up with Tennessee (Danny McBride) and get off the planet, a healed Walter (Michael Fassbender) fights with David (also Fassbender). Before Walter can land the killing blow, David gets him to hesitate while reaching for a knife. The scene ends before we can see the result of their fight, but an android claiming to be Walter exits the structure and joins Daniels and Lope.
After a fight with the xenomorph on the ship where Ridley Scott gets to do his variation on the power-lifter battle from Aliens by having Daniels crush the xenomorph with a crane claw, all seems well with the ship returning to the Covenant. But all is not well! Because there’s zero procedure for dealing with alien species, and even though they just came from a planet where two people died from an alien virus, no one thinks to check out Lope for anything more than his face.
Daniels goes to take a nap, and while she’s sleeping, a xenomorph busts out of Lope’s chest. It goes to the shower room where it kills Upworth (Callie Hernandez) and Ricks (Jussie Smollett), and then Daniels and Tennessee try to hunt the sucker with the help of Walter looking on the monitors. They guide the xenomorph to the cargo bay, there’s a brief fight, and the creature gets double-killed by being impaled by machinery before being sent into the vacuum of space. It’s basically one long action scene that’s designed to kill off the remaining two characters we didn’t know very well.
But it’s impossible to focus on the scene because we’re waiting for Scott to reveal that Walter is actually David. Because we’re left wondering what happened in the temple, there’s no way for us to take the scene at face value, so rather than focusing on the action on screen, we’re trying to determine why David would bother helping Daniels and Tennessee to kill his xenomorph pet.
So they go back to the cryopods, Tennessee gets in his and goes to sleep none the wiser (and apparently having done all his requisite grieving for his wife who died less than 24 hours ago), and Daniels gets in her pod. Before she drifts off, she asks Walter about the cabin he’ll help her build, and caught in his lie, Walter reveals that he’s actually David even though he doesn’t have a puncture wound under his chin where Daniels stabbed him with a nail back on the planet. Daniels passes out screaming, David goes to the embryo room and coughs up a couple of facehugger embryos and puts them alongside the human embryos. He then records a log as Walter saying that all of the crewmembers except for Daniels and Tennessee were killed by the neutrino burst.
So much of this ending makes no sense. Let’s start with David masquerading as Walter. Earlier in the film, we’re meant to believe that Walter is a more advanced version of David, and he can heal from minor injuries (his hand doesn’t grow back, but the hole in his neck patches itself together). If that’s the case, why doesn’t Daniels wonder why Walter has scars on his face? Or, if the ability to heal is something that’s new (and something David clearly didn’t know about), then how did the puncture wound underneath his chin heal?
Furthermore, why would David go to such great lengths to save Daniels and Tennessee from the xenomorph? Does he think that if all the crewmembers died it would be suspicious, but if only thirteen died and two survived, then he’ll be okay? Also, Daniels knows Walter is David, but he doesn’t kill her, so is she just going to be an experiment later for David (probably)?
I guess if you believe that David wants to keep humans alive as test subjects, his actions make sense, but the movie allows far too much leeway in David’s abilities. He can heal when it’s necessary, other characters can ignore his wounds that should be healing, and he also somehow knows all of Walter’s access codes. This is all in service of distracting us for the climax of the movie as we wonder if Walter is David and if so, why is David pretending to be Walter after getting on the ship?
What the ending doesn’t explain: how the xenomorphs got to LV-426, the planetoid the Nostromo crew discovered in Alien. We’re still on that pointless mission of how the Engineer got to that planet and why he was surrounded by xenomorph eggs. Scott says he has one or two more Alien prequel films left. Judging by Prometheus and Alien: Covernant, we’ll still probably be scratching our heads by the time he’s done.