There is an instant animosity between West and faculty member Dr. Carl Hill (David Gale). Hill's theory of brain death bears a remarkable resemblance to that of West's mentor, Dr. Hans Gruber (Al Berry), a professor in Zürich. In the opening scene, West brings this dead professor back to life with horrific side-effects; a result, as West explains, of having given Gruber an overdose of his re-agent. Undaunted, West continues his personal research at Miskatonic, soon re-animating Dan's dead cat, Rufus. Upon Dan's discovery of this, West quickly recruits him as his partner.
Soon the two sneak into the morgue to test the re-agent on a human subject. The corpse revives and goes on a rampage, attacking both West and Cain before escaping into the autopsy room. Dean Halsey stumbles upon the scene and, despite attempts by both West and Cain to save him, is brutally killed by the re-animated corpse. Armed with a bone saw, West finally manages to dispatch that which he's only just brought back to life. Hardly fazed by the violence and excited at the prospect of a fresh dead subject to work with, West injects Halsey with the re-agent. Halsey returns to life, but in a zombie-like state.
Dr. Hill discovers West's work, imprisons and eventually lobotomizes Halsey, while forcing West to continue the research so that Hill can take credit for the serum's discovery. West kills Hill, decapitating him with a shovel, then re-animates both his head and body. Hill knocks out West and escapes, carrying his head, stealing the serum and sending the lobotomized Halsey out to kidnap Megan.
Cain and West track Halsey to the morgue where they find Hill molesting a restrained Megan. Cain frees Megan while West distracts Hill. Hill reveals that he has re-animated and lobotomized several corpses so they will do his bidding. However, Megan manages to get through to her lobotomized father, who fights off the corpses long enough for Cain and Megan to escape. In the ensuing chaos, Halsey is torn to pieces by the other corpses and West injects Hill's body with what he believes is a lethal overdose of the serum. Hill's body takes on a horribly monstrous new form and attacks West, who screams out to Cain to save his work before he continues fighting with Hill. West appears in the next sequel, but it is unclear on how the fight ended.
As Dan and Megan run from the morgue, Megan is attacked by one of the re-animated corpses and killed. Dan takes her to the hospital emergency room but is unable to revive her. He injects her with West's serum. Just after the scene fades to black, Megan screams.
Originally, Gordon was going to adapt Lovecraft's story for the stage but then writers Dennis Paoli and William Norris and Gordon decided to do it as a half-hour television pilot. The story was set around the turn of the century and they realized that it would be too expensive to recreate. They updated it to the present day in Chicago with the intention of using actors from the Organic Theater company. They were told that the half hour format was not salable and so they made it an hour, writing 13 episodes. Special effects Bob Greenberg, who had worked on John Carpenter's Dark Star, repeatedly told Gordon that the only market for horror was in feature films and introduced him to producer Brian Yuzna. Gordon showed Yuzna the script for the pilot and the 12 additional episodes. The producer liked what he read and convinced Gordon to shoot the film in Hollywood because of all the special effects involved. Yuzna made a distribution deal with Charles Band's Empire Pictures in return for post-production services.
Yuzna described the film as having the "sort of shock sensibility of an Evil Dead with the production values of, hopefully, The Howling". John Naulin worked on the film's gruesome makeup effects and worked from what he described as "disgusting shots brought out from the Cook County morgue of all kinds of different lividities and different corpses". He and Gordon also used a book of forensic pathology in order to present how a corpse looks once the blood settles in the body creating a variety of odd skin tones. Naulin said that Re-Animator was the bloodiest film he had ever worked on. In the past, he never used more than two gallons of blood on a film. On Re-Animator, he used 24 gallons of blood.
The biggest makeup challenge in the film was the headless Dr. Hill zombie. Tony Doublin designed the mechanical effects and was faced with the problem of proportion once the 9-10 inches of the head were removed from the body. Each scene forced him to use a different technique. For example, one technique involved building an upper torso that actor David Gale could bend over and stick his head through so that it appeared to be the one that the walking corpse was carrying around.
It was well-received by critics, earning mostly positive reviews with a 92% rating at Rotten Tomatoes. Roger Ebert gave the film three out of four stars and wrote, "I walked out somewhat surprised and reinvigorated (if not re-animated) by a movie that had the audience emitting taxi whistles and wild goat cries". In her review for the New York Times, Janet Maslin wrote, "Re-Animator has a fast pace and a good deal of grisly vitality. It even has a sense of humor, albeit one that would be lost on 99.9 percent of any ordinary moviegoing crowd". Paul Attanasio, in his review for the Washington Post, praised Jeffrey Combs' performance: "Beady-eyed, his face hard, almost lacquered, Combs makes West into a brittle, slightly fey psychotic in the Anthony Perkins mold. West is a figure of fun, but Combs doesn't spoof him". In his review for the Los Angeles Times, Kevin Thomas wrote, "The big noise is Combs, a small, compact man of terrific intensity and concentration".
The film was ranked #14 on Entertainment Weekly magazine's "The Cult 25: The Essential Left-Field Movie Hits Since '83" list.
Stuart Gordon has been quoted on several occasions as expressing a desire to make a fourth installment in the series, entitled House of Re-Animator; this film would, he claims, be a political satire wherein West moves into the White House and re-animates the deceased Vice President. In May 2006, producer Brian Yuzna told Fangoria magazine that the film was indeed being made. Yuzna expressed his desire for a large budget in order to hire well known supporting actors, such as William H. Macy, for the film. In addition to House of Re-Animator, Yuzna hopes to film two additional sequels in order to form a second trilogy.
Recently further information was revealed on Yuzna's website. The three new films have working titles House of Re-Animator, Re-Animator Unbound and Re-Animator Begins.