The plot integrates the neo-noir and buddy cop film genres with a science fiction theme, centering on the relationship between a veteran police investigator (Caan) and an extraterrestrial (Patinkin), the first Newcomer detective.

The Newcomers Hubley, Porter, and Strader were involved in the planning phases of the operation, but were later murdered due to Harcourt's desire to exclude them from any future profits.

One out of twenty to twenty-five stories received each week by 20th Century Fox in 1988, Rockne S. O'Bannon's original screenplay for Alien Nation was submitted as a spec–script to producer Gale Anne Hurd.

Working with co-producer Richard Kobritz, Hurd secured funding from Fox Studios and began casting an experienced makeup team for the creation of the alien society.

Winston was not directly involved in the pre-production, but left the task to his top artists–Alec Gillis, Shane Mahan, John Rosengrant, Tom Woodruff, and Shannon Shea.

After we went into production on these masks, Graham Baker decided that he wanted the aliens to look even more subtle, so we streamlined the design once we started doing the principal characters."

On the other hand, Kevyn Major Howard–who played Harcourt's murderous henchman–had very delicate, boyish kind of features, so we used that quality to create a creepy juxtaposition.

"[3] While effects coordinators were struggling to finish the final design and full-scale production of the alien prosthetics, Hurd chose makeup artist Zoltan Elek to supervise the overall application.

Elek recalled his disagreement with Winston as Stan felt, "... the aliens should be a totally different color than the humans, with a lot of yellows, blues and grays.

"[3] Application of the Newcomer makeup known as "spuds" or "potatoheads" on set, required four hours; a task which Patinkin described as being "a pain in the ass.

Rosengrant noted, "While the dissolving makeup had to look extreme, it also had to appear realistic within the limits of the alien anatomy Winston's crew had designed.

As the Bromo Seltzer started to fizzle, the hot water began eating its way through the gelatin skin and his face appeared to bubble and melt."

The film crew did their own painting and even took a big blank concrete wall and inserted alien graffiti for a scene involving an early physical confrontation between the main characters.

He commented how the crew "came up with individual alphabets and then combined them into certain words like, say, 'enter' and 'open', so that we could repeat them, ..." while also mentioning how they "brought in a language expert to give us something the actors could be comfortable with.

[6] Set decorator Jim Duffy, who was involved with the exotic dance scene at the club, used unique Austrian drapes to create a see-through design for actress Bevis who portrayed the character of Cassandra to perform around with.

[6] A Van Nuys bus stop set stood in as the taco burrito stand for the amusing scene between Francisco and Sykes relating to raw fast food.

[6] The interior of Sykes's house was filmed at a home near the studio, while a location in Beverly Glen stood in for a church in the final wedding scene.

[6] The lobby section of the hotel with its very high ceilings and extensive complement of gold motif, was used in an interview scene between the characters of Harcourt, Kipling and the detectives.

[6] He admitted, "We did build a spaceship, but it's a simple thing that you see on a TV monitor describing the landing of the aliens several years ago, before they became assimilated into our society.

"[5] He went on to say, "I thought it made a tremendous difference to the piece that the guy's name was George Jetson because it gave a cartoon feeling, an innocence that was important to the movie's whole idea.

[10] Musical artists Smokey Robinson, The Beach Boys, Michael Bolton, Mick Jagger and David Bowie among others, contributed songs which appear in the film.

[16] The Region 1 Code widescreen edition of the film was released on DVD in the United States on March 27, 2001, and includes a narrative and interview filled Featurette, a Behind the Scenes clip featuring director Graham Baker, a TV Spots special, the Theatrical Trailer and Fox Flix theatrical trailers for The Abyss, Aliens, Enemy Mine, Independence Day and Zardoz.

Regarding the fictional alien culture, he expressed disappointment saying "a feeble attempt is made to invest the Newcomers with interest, by having them get drunk on sour milk instead of booze, and depriving them of any sense of humor."

However, on a slightly complimentary note, Ebert mentioned "the makeup took trouble, the photography looks good, the cast and technical credits are top-drawer."

"[22] However, the more enthusiastic staff of Variety found originality in the extraterrestrial–injected plot, saying, "Solid performances by leads James Caan and his humanoid buddy-cop partner Mandy Patinkin move this production beyond special effects, clever alien makeup and car chases" while also adding the film was a "compelling human–humanoid drama.

"[24] On a negative front, author Jay Carr of The Boston Globe commented on James Caan's performance, viewing him as "Looking like a Paul Newman gone wrong, ..." He went on, further stating that "the film's air of enlightenment is only makeup deep.

"[25] Other critics such as Gene Siskel acknowledged the similarities between other police thriller movies, but still found the film to be a "Genuinely entertaining version of that old reliable; a cop buddy picture with two very different detectives."

A summation of the negativity was, "Played hard and fast, the film might just have worked, but the decision to soft-pedal the violence merely emphasizes the obviousness of the liberal point-scoring (parallels with Vietnamese or Nicaraguan refugees are so facile as to be crass).

Alien Nation: The Udara Legacy, finds the detectives trying to stop a resistance group among the Newcomers trying to indoctrinate those among them into causing mayhem.

In 1993, Pocket Books, a division of Simon & Schuster, published a novel series, including the Judith and Garfield Reeves-Stevens' Day of Descent,[39] Peter David's Body and Soul,[40] along with Barry B. Longyear's The Change[41] and Slag Like Me.