There have been many movies based on the writings of Howard Philips Lovecraft, most of them lacking the truly eerie qualities of Lovecraft's weird tales. In fact, horror films and science fiction films with little or nothing to do with Lovecraft have often done better at representing the themes Lovecraft addresses in his writings.
Lovecraft fans have had to endure:
Die, Monster, Die -- a theatrical version of Colour Out of Space.
The Dunwich Horror -- Roger Corman AIP Production.
Reanimator -- A cult classic, and fun sure, but not exactly horrifying.
The Unnamable -- The less said the better.
From Beyond -- I wish it had stayed there.
Sure there are many more, but I have seen the films above and they have played their little games with my psyche. Surely nothing could be as Unspeakable as Unnamable
Now Lovecraft fans have Cthulhu. All I have to say is that my first glance at the trailer made me think the film might be enjoyable, but then I saw the madness bringing work of the Old Ones had indeed infected this film. For the film's cast includes Tori Spelling. If that doesn't require a Sanity Check...nothing does.
Ia! Ia! Cthulhu Fhtagn!