Verdict:

There is so much great about Alien that it is hard to know where to start. Let us start with the artistic title screen. Against the background of outer space, the word “Alien” is very slowly formed, setting the slow but tense pacing of the film right from the start.
The film is about a crew of a spaceship dealing with a hostile alien encounter. Alien is built on a relatively cliché horror movie formula of a killer taking out the victims one by one. However, it layers enough interesting material on top, which ends up making this movie feel very unique. For example, it does have jump scares, but most of them make sense in the context of the plot (though the cat scares, I will say, are quite egregious). The movie also follows the trope of separating the group, but the way the reasons for the separations feel sensible.
Not everything in the storyline makes sense and it is not a perfectly smooth ride, but the blemishes are very insignificant.
Furthermore, Alien is one of the most original looking films and its looks hold up well, even today. The mock up models of the main spaceship do unfortunately look like plastic, but the interior of the ship looks awesome. The bright off-white design of the living quarters mixed with dark industrial corridors provides variety for the eye. The old CRT computer screens and the mechanical keyboards may look outdated but, not only do they fit well with the overall design, the austere small screens with static and few colours add to the overall creepiness and claustrophobic mechanical feel of the environment.
The alien designs were done by the wonderfully insane H. R. Giger. His designs are unique and nightmarish but at the same time believable and natural looking. When you see an alien creature move inside an egg, it looks real. The sexualized style of the art is present throughout the film, though made more subtle than Giger’s original work (please look it up if you haven’t yet). Sadly, the technological limitations mean that, while the design of the creatures is cool, when those creatures move, it looks bad and in some cases unintentionally funny.
The sound design is responsible for about 40% of the creepiness in this film. Chilly space-music with little to no rhythm is mixed with various sound effects that are not always caused by anything specific on screen but that nonetheless integrate themselves into the the environment to make a cohesive whole.
All the Little bits contribute to this movie’s unforgettable atmosphere. There is a brief scene where the characters just quickly go over the composition of the alien planet before they go outside. Was the scene necessary? No, but is a great way to build the world and establish atmosphere. The distorted shaky images of the helmet cams, the cramped conditions and the creepy sound effects combine to make a most intense film.
The actor performances feel very realistic. It is believable right from the start that the crew members are people who have worked together before. Apparently, the director actually made the actors spend time together, so that they would be well acquainted by the time the filming started and this paid off. However, a minor complaint is the lack of shock or surprise in the reactions of the crew, when some of the messed-up events take place.
Sigourney Weaver delivers a very strong performance as the intelligent strong officer who tries to stay in control of the situation. The other notable performance is from Yaphet Kotto, as one of the mechanics. He feels the most natural, like an actual worker on the ship.
This film is not perfection. Not all of the scenes may be strictly necessary, not everything looks timeless (especially now that it’s remastered), not all dialogue has a purpose and the performances are not Oscar worthy, but taken as a whole, Alien is such an interesting and effective film that it can be rightfully called one of the best movies of all time. Its influence on the industry and pop-culture is enduring and justified.