The best scenes in Alien Covenant are basically a re-write of the best scenes in the most maligned Alien movie of them all (at least without a Predator in the title) -- yes I speak of Alien Resurrection, with its horrific Ripley clone wax museum and eroticized strangeness. (Yes Covenant's already legendary flute scene is its best scene, obviously.) In Covenant all of this is crammed into the second act, and here the movie (although largely devoid of actual alien action in these moments) achieves its own momentarily hallucinatory magic, with wind whistling down stony corridors with multiple Fassbenders flitting in between.
After a Blade Runner-ish prologue the first act of Covenant feels like a reboot of Scott's own first Alien movie (with some Gravity sprinkled on top for good measure) and the last act is kind of a rushed re-staging of Cameron's Aliens - altogether you could say that Covenant is kind of a Frankenstein's Monster of the entire franchise, hoary bit stapled clumsily to hoary bit. But we're talking about Karloff's movie Frankenstein, big and lumbering and dumb, decidedly not Mary Shelley's book Frankenstein, which raised an eloquent aberration at its morbid center. This thing is plods and groans.
Oh Covenant thinks it's a smart one though, and it's suckered in a lot of smart people too - I've seen defenses of its dumb characters (Ridley just thinks people are dumb!) and its lousy logic (it's just the logic of a nightmare!) but it all just read as lazy and sophomoric half-assery from where I was sitting. Scott strains for an interstellar fairy-tale but this is no Space Suspiria - this is no dream. Yes Rosemary, yes Ripley, this monster-baby is really happening.
The nonsense just piles too high too fast. Smart characters acting super dumb can only be so tolerated, especially when you're forced to listen to them spout philosophy and take it seriously at the same time. Even besides the "people poking strange things with sticks" and the "wandering off into caverns alone with known villains" Z-grade slasher-movie stupidity there's just no coherence to the film's timeline - face-huggers turn into chest-bursters turn into ten-foot tall xenomorphs within minutes when dictated to do so by the rando needs of the plot; entire sections seem stomped into acidic mush.
To be honest I think I liked Prometheus better - Prometheus was just as dumb but it had a couple of for-the-ages scenes, and the scenery was at least a little lovelier to look at, Scott's camera allowing us long and lingering looks at those strange alien worlds. Every time I thought I was seeing something beautiful in Covenant the cutting went and mucked it up, and some of the CG here is goofily amateurish. (Egads that baby chest-burster was positively Spaceballs-ian.) I walked out of the theater shrugging, a bit dazed, but in the 48 hours since I've birthed my own rage baby - this thing's a mealy-brained blight.