The violence is fairly moderate. It is nowhere near as graphic as the remake.
A man is discovered impaled to the wall of an outhouse. Some blood is on him.
After a dog is killed, it is briefly shown with its guts ripped out. Per Wes Craven, this was a real "dead dog" that the production purchased for the film.
A man is burned alive, his horribly charred body is seen several times during the rest of the film. At one point a mutant starts eating the man and is seen chewing his flesh.
A bird is taken, has its head ripped off, and it's blood squeezed into the mouth of a mutant. You don't see the bird at all, just blood squirt out of a closed fist.
Two people are shot; this is not very bloody, and shown for a second.
A mutant is stabbed; blood pours out of the wound.
A mutant is attacked by a dog twice. The first time, his ankle is ripped open, shown in a very graphic close up, and the second time, his throat is ripped open until he dies. This is shown in quick, extreme closeups and not very graphic at all.
A mutant has a hatchet embedded in his back. When this fails to kill him, he is shot several times.
Another mutant is stabbed many times, but this is shown in first person, so not much blood is apparent. A little is on his corpse afterwards.