Horror Western film subgenre is unappreciated and underexploited
Combining traditional American old-West movie backdrops and themes with supernatural/monster horror (not sci-fi) is not new but rare. Perhaps it is because blending the two is a challenge. But it's been done on a few occasions.
THE BURROWERS (2010)
Sorry...I just can't recall the titles of the others right now but will come back and edit this when I do.
Western horror, or, horror western, often provides an interesting respite from either genre by offering something different. Now Western horror can be limited because, well, the time period and the location are limiting factors. Still a lot can be created with the proper width of imagination.
I thought RAVENOUS did a splendid job of representing western horror. Perhaps that's where much of the criticism originates. Viewers don't know what to make of the concept and so are bewildered.