Hail Satan! Haaaaiiiiiiiillllllll! This low-budget cheapie from the early 70's is one of my favorite movies of all time. Everything works here! It may not be oscar quality, but you'll never see a story as twisted as this come out of big budget land (Hollywood). While it isn't very graphic in its depiction of zombie attacks, it manages some cool and very dark atmosphere.
The characters, as some of the others have noted, are a little annoying, but some of that is due to the fact that this is a drive-in movie. The script is actually quite ambitious, and the actors, almost all unheard of before or since, do an incredibly good job with their parts. One thing I will say is that you need to stick with this one for a while because the zombies don't attack right off the bat. While this is a zombie movie of sorts, it isn't your standard zombie movie, and certainly doesn't stick to the regular zombie mythos. These zombies aren't your run of the mill chumps! They are fast, strong, incredibly vicious and won't give up or go away until everyone is dead. These zombies are more like hell-spawn than mindless reanimated corpses.
Had there been more gore, I think this movie would be better received by the horror crowd. Believe me though, the lack of gore scenes doesn't really hurt this movie at all. Give it a chance, and if you didn't like it the first time, give it another!
8 out of 10