While each of the three movies is very distinctive, there are certain core elements that bind them together and unite them. Those are what I would call a classic Alien elements, which had been absent from other Alien movies beyond the original trilogy, if not all, at least some of them.
I. Sets
In Alien, the sets could easily pass for interiors of an old submarine or a cargo naval ship. In Aliens, the sets could easily pass for a power plant or cargo storage. In Alien 3, they look like old infirmaries or led works.
Nostromo's dining room and livable space were clean, but the ship was old and battered, and it had rumbling engines, leaks and seemingly old machinery in its guts. Sulaco was the same - its livable space was clean, but not new, not sterile and the ship's heart was rambling all the time. We didn't see its guts but knowing it had been designed with functionality in mind rather than aesthetic, we can assume it's down and dirty as well. It seemed real, the docking bay, the chains etc. Nostromo looked very crude and industrial in its interiors, Sulaco looked not far removed from Naval storages (docking bay) and your average mess hall (stainless steel everywhere).
Used doesn't necessarily mean stained or dirty. It's about the design, the look, the feel.
If you take shots of some of the interiors on Nostromo and show it to someone , chances are that someone would never tell it's a scifi movie spaceship. They could think it's submarine's interior for example
Same with Aliens, show The Atmosphere Processor and people would think it's a power plant, show them Operations, and some would think it's a flight control tower interior. No one would say it's obviously a futuristic sci fi action atmosphere processor on a different planet or a colony communication room in a distant planet colony from the future
Same with Alien 3. Show some shots of the sets and people would think it's infirmary or regular dining mess hall, or even a church instead of a space colony on other planet from a futuristic scifi film
Resurrection swept that away and reduced the series to that random and common futuristic scifi look.
Even the scientists have suits like admiral suits from Star Wars
II. Characters
The Alien Trilogy I love almost equally. It had a lot of elements that set this series apart form other scifi series'. It had a lot of common traces, and the strong link to our reality, the way we talk, environments and characters was one of them. It was also the first to do this, to present that blue collar environment in characters as well as designs that we can connect to, that we subconsciously recognize.
There was no need for any whacky futuristic sterile space uniforms. Clemens had recognizable medical gowns, yet he was over a century in the future. That's what set the first 3 Alien movies apart from other scifi. The alien series went from 2 engineers in shirts and baseball caps talking about paycheck, food and sex on a towing cargo ship to evil scientists creating mutants on a floating genetic laboratory and space pirates with custom clothes....(the fourth movie)
And Alien was set over a century from now, yet everything in it is recognizable, old machinery, clothes, etc. That was that distinctive thing about the it, future that seemed like today or even a past. No labs, no futuristic uniforms. It was a retro future
The beauty of the first 3 Alien movies was that characters reflected the real everyday character of our lifetime. The Nostromo crew was like your typical, next door blue collar working class neighbor. Aliens showed the Vietnam era soldiers who act like typical young draftees (I lived in a country where you still got drafted to the army up until few years ago so I knew plenty of young draftees and the Sulaco team is a mirror reflection of them). The prisoners of Alien 3 were bald, obnoxious and pretty much acting like any slimes in prisons, or Brit hooligans.
The Betty crew is another reason why I hate the Resurrection movie. Those people look like video game characters. Tough guy with dreadlocks with double guns shooting upside down like its Die Hard, handicapped funny guy with gadgets, Pearlman with muscles and one liners, and those outfits. They look and act like video game characters and Mortal Kombat rejects. Good luck finding a bunch like the Betty crew in real life. At Comic Con as cosplays maybe
In resurrection, even the scientists have suits like admiral suits from Star Wars. Why the need for some whacky futuristic sterile space uniforms? Again, Clemens had a well known gowns, yet he was over a century in the future.
III. Alien
Another thing is that the trilogy showed the Alien only in quick cuts, as shadows or in the darkness or mist. They were portrayed as shadowy figures that lure in the dark and are usually seen only for a split second. Latter films showed them in full bright light in lingering shots
In Alien, we only see alien in the dark or in the mist. When we see him fully, its only in quick and distant cuts outside the shuttle, or in strobe light
In Aliens, we only get to see the alien if we freeze frame as they mostly appear in the dark, as shadows and silhouettes
In Alien 3 we see the runner in full light (although dimmed as well) for one second in the infirmary - as in the other 2 movies, we only get to see him in very quick cuts. We do see the closeups of its mouth sometimes, but the full body is always hidden by the orange light, darkness or mist.
People knew how Giger's Alien looks like very well in 1979 already - the toys and posters showed the beast in detail. Yet in Aliens we've seen even less of the creature than on the first one. And even by 1992, when everyone knew very well the Alien after Aliens, we still saw it only partially hidden or in quick cuts.
Alien showed the creature in strobing light, mist and in the dark. Aliens showed aliens as shadows and silhouettes and the Queen in a dark chamber and darkened bay, often with flashing emergency lights. Alien 3 showed the monster in quick cuts and in a mist.
Aliens' mystique and name is ruined. While in other movies they were portrayed as shadowy figures that lure in the dark and are seen only for a split second, In Resurrection theyre constantly shown full in broad light, and now trapped and trained like puppies.
And here we have Resurrection in which camera focuses on the aliens like on people and we see them in a full, bright lab light. No mystery, no suspense, just slimy monsters, not some repulsive thing looming in the shadows. Its all about presentation. For example, this is the same design and same movement/scene. Yet lightning and presentation makes such a big difference. Even AVP got it right. This is the same shot yet lit differently. Also, in Resurrection, the aliens growls like monsters, while in the original trilogy (and in AVP) they have a creepy squeal
The design of the alien itself looses ALL the art of biomechnicality and sexuality, and closely copies the design of the Pumpkinhead who was designed by the same people who did Alien Resurrection aliens
What I like most about the Giger design (those elements were carried over to Aliens and some to Alien 3) is the phallic head shape and the design that looks like a machinery fused with charred skeleton. I love the industrial hoses and cables that are part of the alien body, even such mechanical details like pins and screws on its hips. Outside of the headshape and overall skeleton look, what I also like about them are the sexually suggestive designs on the abdomen, parts reminiscent of penises, mixed with hoses, and the alien even has an open vagina on the crotch. Its quintessential Giger
From A:R on, theyre god awful, god awful. Aliens look like skinny bodies, not skeletons, the head shape is different, the mouths are different, the entire body was redesigned..on and on and on
I really like that original Giger design, the phallic shape of the head with that glans at the end and the overall mechanical parts all over the body, such as tubes, water valves and parts. It makes the creature really a surreal artwork of sex, corpse and industrial parts. Res completely discarded that in the physical design
The head lost not only all the biomech art, but its shape wasnt even sexually suggestive anymore, and was turned into a cockroach head
The second worst thing after the cockroach shaped head is that they completely removed biomechanicality and turned it into some fleshy organs.
H.R Giger on Resurection aliens in a 1999 interview “The Aliens themselves were not well sculpted or sharply defined. It seemed as if no molds had been made and as if the creatures were roughly shaped with mud.”
Other times he was even more blunt on the subject: “I always wanted my Alien to be a very beautiful thing, not just something disgusting, not just a monster, but something aesthetic. Throughout the creature’s evolution what they’ve done is change it from something aesthetic to something that looks like shit – I mean literally, it looks like a turd.”
~ HR Giger, Alien Evolution, 2001.
The A:R aliens are also blatant copies of the Pumpkinhead design (incidentally, same guys who designed Pumpkinhead designed the A:R aliens), and move like him too (arms spread out, leaned forward, whacking head from side to side)
I really dislike the Res design and I really believe ADI just wanted to repeat their own design of Pumpkinhead
Just a thought