Friday the 13th Part 2/4?
ANOES 3/4 (for entertainment/fantasy purposes)?
Are some some that quickly come to mind that are far more powerful than the impact that Halloween 2 made. All Halloween 2 is missing is John Carpenter. Aside from that fact, it's a great little horror movie.
Hell, I even like House II: The Second Story better than House. I found the sequel to be far more entertaining and fun, while the first was boring...