Alien: Perfect suspense horror.
Aliens: Perfect suspense action.
Alien 3: Some big mistakes, but decent performances. I prefer the DVD box set extended-cut to the theatrical.
Alien Resurrection: Also some big mistakes but it's solid b-movie comic book fun. Love Sigourney... but I wish the film were smarter.
One thing that bothers me about the Alien series is all the time jumps. I understand that Alien takes place in the year 2115. I can buy that. It would probably take that much time to get us into space so often that we'd have regular freight routes like the Nostromo might use. Then Aliens jumps 57 years to 2172 and that's fine since that duration seems plausible enough for Ripley to have been floating around out there (her daughter and friends back home have passed on, she's Sleeping Beauty). Aliens leaves her, Newt and Hicks in cryostasis again until Alien 3 picks up... when? My research doesn't turn up a listing for the year that Alien 3 takes place in, though I feel that it's meant to take place immediately after Aliens. So, timewise, Aliens and Alien 3 are pretty much one long movie. And after Alien 3 comes to a close, we jump 200 years ahead to Alien Resurrection, presumably set in 2372.
And all that's changed in 250 years, from Ripley's basic Alien timeline and the Resurrection timeline is... Cloning? Laser-melted alcohol? Sexier androids (Ryder)? Galactic freighters don't seem to have changed much, nor language, recreational sports (basketball), sexual attitudes (Perlman) or wheelchairs (Pinon). That's what always bothered me most about Alien 3 and Alien Resurrection: that there just wasn't enough imagination in them. Scott's Nostromo is both a nightmarish hanuted house in space and a giant live-in truck, basically sent out there to gather materials and transport them home to Earth, isn't it? In film, it's pretty much the first of it's particular kind (aside possibly from Dark Star and maybe Silent Running). Cameron's vision of LV-246 is still unmatched to this day in it's realistic-feeling workaday portrayal of the terraforming colony and far more sprawling and even daring in its tech visions (the anime-like cargo-loaders).
Alien 3 and Resurrection feel been there done that in design and portrayal. The "wooden planet" from Vincent Ward's take on the screenplay sounded promising, though, if only intellectually (and perhaps an early spiritual sister to Aronofsky's The Fountain). It must be daunting from a design and storytelling sense to have to come up with a cinematic future like nobody's ever seen before. The Fifth Element seemed a poppy, happy take on Blade Runner via The Jetsons. The vision of Zion and the scorched surfaces of The Matrix Trilogy got deeply earthy (literally so). Right now, the only futurist vision that comes to mind as being somewhat fresh is the one of Spielberg-and-Kubrick's A.I.: Artificial Intelligence. Love it or hate it, the combination of technology and nature (oceans, fields) paints what feels to be a future within something akin to reason, whereas Spielberg's Minority Report comes fairly close except for the auto-drive freeways and cryo-prisons.
In this way, it's interesting to me that Ridley's gone back in time a bit with Prometheus. Closer to our (the audience's) present time than any of the Alien films, his concepts of a world between the now and the far-off imagined have me wondering just what ol' Ridley's got waiting for us. By taking the huge gap leaps through time from Alien 3 and Resurrection out of the Alien equation, he might be giving us something unexpected -- an imagined future we could possibly relate to. This story might not deliver any forward looking predictions of still-further technical times, but then again this story seems not necessarily to need them. We'll see our future soon enough. In both the cinema and reality.
Read all about it:
ALIEN 3 - Vincent Ward's "Wooden Planet"
The Unrequited ALIEN 3
The ALIEN Quartet by David Thompson