This was the second Marvel magazine with the title Haunt of Horror; this one, however, was of standard magazine size, and made up of standard comics stories rather than prose.
This Haunt of Horror was typical of Marvel's monster magazine output of the time, mainly of stories featuring visually satisfying monsters and protagonists, which fit in seemlessly with the company's usual superhero fare. A few text articles on related subjects - such as a long treatise on the then-popular Exorcist film - were also mixed in with the fiction. The artists and writers came from the company's regular stable of talent, though they could let themselves loose a bit more since the magazine format allowed a bit more freedom that regular-sized comics could not.
Similar to the digest issue #3, a sixth issue was planned but never materialized.
Note: Confusingly, there was an issue of Marvel Preview featuring the title Haunt Of Horror on the cover, which came out in 1977.