I enjoy running horror-style adventures in my D&D campaigns, though I've only run them as "one-shots" or side quests.
Hangman's Noose presents an introductory adventure to kick off an entire horror-style campaign, and it does so very well.
The adventure jump starts into a horror-movie scene that's part Twelve Angry Men, part Final Destination, part Haunted (1995 Aiden Quinn movie), and a mixture of classic horror elements.
The conclusion of the adventure includes information that could be used to continue a horror-style campaign, all of which take place within the same city of Absolom.
This adventure succeeds in presenting horror elements in D&D by providing the descriptive narrative that horror stories need. It also uses the D&D mechanics to produce some other horror-movie aspects, which, to me is the most important aspect of running a horror game in D&D.
What I mean by this, is the players need to know that their spells, feats, skills, and class abilities still work the same way, and anything that the horror-style creatures or effects do can be explained by looking at the rules.
At the same time, the horror-elements should be part of the story, not the star of the show, stealing away the PC choices and abilities. There are encounters in the adventure that seem to "have to happen" and the players can't stop.
While this does produce a classic horror-movie effect, it takes away a vital aspect of an RPG, which is that the players actions have an impact on their surroundings.
Of course, these events can easily be adapted to better suit the style of play that the DM and the players enjoy.
All in all, this is a solid D&D adventure, and an outstanding horror-style adventure. For more inspiration of running a complete horror-style campaign, I recommend picking up Heroes of Horror and Dragon Magazine #336.