Halloween II (1981)- it was directed by Rick Rosenthal (who laughably did Resurrection) but Carpenter came back and did reshoots to cash in on the slasher craze. A couple death scenes really push the boundaries. The mom escorts her son into the hospital with a huge pin stuck inside his mouth (from eating tainted candy), and the lead nurse laying on an operation table bled to death from an i.v. It was contrasted with some light humor when Jimmy sees her laying there and tries to exit quickly. He slips on the massive amount of blood and falls and hits his head and knocks himself out. There has been plenty more gratuitous examples out there, but not really more disturbing because of its suggestion.
I think the reason why I keep watching the film is because even though it's just a body count film there's really nothing quite like it in its best moments. The idea Myers was this force of evil, and that's really never been captured better in part 2 because it's all set at night. I can remember people wondering why the hospital lights went down, and they do show Myers doing *something* which implied to me he took out the phone lines and maybe the lights. But it was because they had too. I've seen photos of Myers on set in the light and that pretty much answers why.
I still thinking the ending is the pinnacle of the franchise in regarding to Myers. Before shooting him Laurie calls out "Michael!," who tilts his head as if to remember who he was for brief moment. Then he gets shot in the eyes but still is flailing with his knife. Some don't like lord helmet Warlock's portrayal of Myers, sighting it as too robotic. But I rather like it. With Laurie being mentioned as his Myers' sister, he now has a motivation. Really he had to since the original is a one-and-done. As another mentioned, it was a stroke of genius by Carpenter.
They've never really been able to capture Myers as a force of evil again after the Carpenter years. I think photographer Dean Cundey was instrumental in helping get that out. Even in part III the robotic assistants come across as this force of evil. Carpenter tried to achieve that with The Fog, but how do you make a fog a force? LOL. They did it again with Christine as this unstoppable force.