I've seen that film, but I didn't think too much of it.
I felt that just didn't convey the proper Lovecraftian feel; it had all the right elements: isolation, building up to something being wrong, a lack of a heroic ending, people dying awfully, etc, but it just didn't have the same feel that reading the stories does. In essence, it had all the right ingrediants, but they weren't baked right.
The most probably reason for that, IMHO, is how the plot developed...it quickly turned into a survival-horror type thing, like a Resident Evil game. The hero, Paul, ran around avoiding the zombie-like townsfolk, fighting some of them now and then, is captured, escapes, and goes to fight back again, and then the movie pretty much ends when the last few characters are dealt with.
This classic movie about a cult is destined to be nothing more than a cult classic.