The Rat from Hell 
A Manhattan executive (Peter Weller) deals with the rats on Wall Street while defending his brownstone ‘castle’ against a literal vermin. Jennifer Dale plays his secretary while Lawrence Dane and Kenneth Welsh are on hand as colleagues.
"Of Unknown Origin" (1983) strikes me as a Stephen King yarn, which makes sense when you figure that this is one of the horror author’s favorite flicks. 
While the compare/contrast of the protagonist’s life in his home-castle with the rat maze at work is interesting, the premise is too light IMHO to carry a feature film: a man vs. a rat alone in his gothic abode. Weller works well as the resolute hero but, for me, the best thing about it is winsome Jennifer Dale (Cynthia Dale's older sister).
Gene Simmon’s wife, Shannon Tweed, makes her feature film debut in a small role. 
The film runs 1 hour, 28 minutes, and was shot in Montreal. 
GRADE: C