Like Ray Bradbury, H.P. Lovecraft is almost impossible to get right. Stuart Gordon made two decent attempts (Re-Animator and Dagon), fine films, but they don’t really qualify as Lovecraft. The Dunwich Horror comes pretty close at times, but Dean Stockwell’s mustache gets in the way.
In the end it’s Dan O’Bannon’s The Ancestor, an adaptation of Lovecraft’s “The Case of Charles Dexter Ward”, that comes the closest. There are stretches (especially towards the end in the underground laboratory, where it gets amazingly close.), a “feeling” of dread that comes as close as anything has. (oddly, it’s that same feeling Dan managed to bring to the original draft of Alien).
The Ancestor you say..?
Don’t bother heading over to IMDB to look it up. You won’t find it. The film was taken away, re-edited and butchered beyond belief. You can find it a full screen DVD of the butchered film under the title The Resurrected.