The potential was clearly there for something good, but the poor casting really holds this back. What we have instead is a barely adequate action film about two police officers—David Carradine and Richard Rowntree—investigating a killer who brutally severs the heads of his victims, often while they appear secure on rooftops or other high places. Simultaneously, “Quinn” (Michael Moriarty) is attempting to evade those he’s indebted to, and during his time spent concealed on top of the Empire State Building, he comes across something unexpected! As the killings become more frequent, and reports of an unusual being reach the police department, he makes an agreement with them to disclose what could possibly be its lair. The narrative itself isn't bad—however, there are simply too few appearances from this enigmatic creature, and the storyline is also weighed down by some Inca rituals. When we finally do see "Q," it’s certainly no Ray Harryhausen production; it possesses a low-budget imitation of the “Hammer” style, and the performances and script aren't any better. It carries an 'X' rating, but I believe that’s primarily due to some nudity—there isn’t anything genuinely frightening to be found here.

Source on TMDB