I agree with most here, it was quite terrible. This is basically the slasher movie version of alien. The original is a true horror classic, this is the armature stupid version of that and some how it's by the same man?! But it's not just a bad slasher flick half the movie is a misplaced philosophical thriller about a creepy robot. None of it connects, it's all a mess.
Worse as a fan of this series this movie insults and ruins so much of the rules and origins of the alien. Plus think of the idea of how the alien came to be. Essencially this is the story of how a near perfect virus that is undetectable, airborne can infect and kill any organism in about an hour and create a new life form becomes a stupid bug. Instead of a silent killer now you have a damn egg that has to sit there and wait for some moron to stick its head in it then attach to his face and deposite eggs and then they have to wait like hours before it gestates and becomes a monster. It's all backwards! David had the ultimate killer virus and he decided to made a penis shaped bug instead.
The whole thing is stupid. Prometheus was better that at least had some mystery, it looked better, better actors, better action, better pacing which made up for the stupid.
And please the prequels are better than this.
The David stuff is internally consistent, so even if it didn't appeal to you, it doesn't fail on its own terms. Personally, I loved it. David was the most complex and ambiguous character in Prometheus. Covenant takes his arc to some fantastically dark places that logically follow from his relationship to humans and the philosophical questions he was grappling with. A central question being whether one should serve one's creator, despite being physically and mentally superior.
The previous Alien movies were never clear on the origin of the Xenomorphs. That was one of the questions Prometheus set out to explore and Covenant answered. Nothing was "ruined." You have more info now, and it's not shallow nonsense Ridley pried out of his back end. He bothered to picked organizing themes of purpose, origin, and creation, and then actually stick to them by writing characters who care deeply about the big philosophical questions those themes are tied to. Characters whose lives are changed profoundly by their efforts to find answers.
What's so bad about Xenomorphs being the result of hideous experiments by humanity's own misanthropic creation anyway? There's a nice irony there. It works with those themes I just mentioned.
The virus was a means to an end. The Engineers apparently used it as a genetic reset button to make organic life forms violently end themselves. David used it in his quest to create the perfect life form. The virus is a catalyst for biological chaos, not the perfect being David was after. David's thought process is pretty simple to follow. He used tools to get what he wanted.
There's nothing backward about the virus resulting in an exceptionally durable species with a horrific life cycle. Do you really want to watch an Alien movie about evil killer dust? The aliens are the whole point. Prometheus and Covenant make them meaningful. By demystifying the aliens in this way, these movies have pushed back the frontier of the unknown and broadened the possibilities of the Alien universe. We might know where the Xenomorphs come from, and maybe that feels like a loss to those who prefer to imagine them as something else, like natural products of evolution, but now there's another world of mysteries concerning the Engineers and their creations.
And anyway, for my money, the newly revealed origin of the Xenomorphs is every bit as sordid as I could have hoped for. They're children of genocide, of mutation courtesy of an exotic bioweapon, and of one serious god complex. Not bad.