While shooting on location in New York City, Captain Haggerty, who plays the large bald zombie who attacks the harbor patrol at the beginning of the film, walked into CBGB's (a tiny Bowery bar which was a flourishing punk rock venue at the time) in full zombie makeup complete with splattered fake blood and mud caked all over his face and body. Due to the outrageous punk styles in those days of the other bar patrons, he was barely noticed. Even the bartender never looked twice at him.
Since there was no CGI at the time, and the production didn't have the budget for fancy animatronics, a real tiger shark was used for the infamous zombie vs shark fight scene. As the tiger shark is one of the most dangerous shark species that exists, the shark's trainer Ramón Bravo fed the shark right before filming as well as doping it up with sedatives.
Despite being called "Zombi 2" the film is not a sequel to anything. When Dawn of the Dead (1978) was released under the title "Zombi" in Italy, this film was retitled "Zombi 2" to cash in on the success of the American film. This was done by the studio without director Lucio Fulci's permission or knowledge, and he often told fans this wasn't a sequel, and that it is its own film. He was relieved to find out the film's actual title "Zombie" was kept in the American release.
The zombies in this film were modeled to resemble the original voodoo legends of the walking dead from Hatian and Caribbean legends of people being reanimated after death. In contrast to the zombies in George A. Romero's Dawn of the Dead (1978) and other zombie films, nearly all of these zombies walk with their heads down, their eyes closed, and with their arms always at their sides. Only three zombies featured have their eyes open.
As shown in trailers before the film was released, airline "barf bags" were handed out to theater moviegoers due to the unusually high amount of violence and gore for a horror film of that time.