I think this film must have had a huge influence on Hatchet, as the monsters in both films are on a secluded island, look similar, and communicate only through grunts. They both also have superhuman size and strength. That film actually shows why the dark cinematography in this film was the best approach. In Hatchet we see the monster too clearly, and he's neither scary nor is his make-up particularly convincing.
Not quite as good as Prom Night, but you could do worse. Paul Lynch certainly knew what he was doing. The soundtrack was also really awesome, sort of resembling the work of italian composers like Fabio Frizzi and Claudio Simonetti!