Nightmare City

Nightmare City Italian Incubo Sulla Citt Contaminata is a 1980 ItalianSpanish zombie film directed by Umberto Lenzi. The film stars Hugo Stiglitz as a television news reporter who witnesses the collapse of order in a city overrun by irradiated blooddrinking ghouls. Victims of the ghouls rise from the dead to join the host, adding to the chaos.

Military scientists determine the attackers are contaminated humans whose tissues have been mutated by radiation. Their bodies, while capable of feats of strength, speed and reflexes beyond those of most humans, are unable to regenerate red blood cells, hence their appetite for blood. Miller and his wife escape to an abandoned amusement park that is also overrun with ghouls. They climb to the top of a roller coaster where they will be rescued by a military helicopter, but Anna falls to her death. Miller then wakes up, revealing the whole situation to be a dream. Miller also learns that today he is about to meet a scientist at the airport. When he arrives, a military plane makes an emergency landing, repeating the events of the beginning of the film.Director Umberto Lenzi felt the film was not to be labeled as a zombie film but a radiation sickness movie with hints of an antinuclear and antimilitary message. ........

Source: Wikipedia