If you have a low tolerance for blood, Demons is definitely not for you. It's loaded with multiple stabbings and blood dripping everywhere. The "demon ooze" is also totally disgusting. It can be best described as a tsunami pimple that erupts with brutal force. It even made me squirm a little bit which doesn't happen very often. While Demons would not be considered torture porn, it's pretty violent stuff.
Demons also boasts some crazy special effects including fingernails growing into claws and teeth falling out, only to be replaced by gnarled, crooked fangs. With the help of contact lenses and a little green slime, the demon look is complete. It's actually quite good and skillful especially for the time period of the movie.
A sequel to Demons was made the following year. While IMDB rates the original higher, I actually prefer the sequel in terms of storytelling, its artistic sense of style and the fact that its a bit lees gorier than the first. See both if you like to have a gross out good time.
RATING: Very Good.
For more info check out the film's entry in IMDB.