NIGHT OF THE ZOMBIES (aka HELL OF THE LIVING DEAD, aka VIRUS, aka ZOMBIE CREEPING FLESH) moves at such a maddeningly slow pace, it's an endurance test just to stay awake. Almost all its attempts at horror, whether it's gore or atmosphere, fall flat, and it's plagiary of dialogue, plot points and even MUSIC (stolen directly from the DAWN OF THE DEAD soundtrack) from it's superior predecessors is shameless.
What can you say about a movie in which the most interesting aspect is the "Mondo" stock footage (which comprises nearly a fifth of its running time)? There's some decent gore at the end when the lead female character has her head hollowed out, but mostly it's the usual animal guts, maggots and fake blood any spaghetti splatter fan has seen dozens of times before.
An inexplicable box office hit that marked the beginning of the end of the 42nd Street splatter movie.