Of course, the other reason that IT feels like such an 80s nostalgia-fest is that the story itself was a major inspiration for Stranger Things, which was designed to be an 80s version of IT before IT was actually set in the 80s.
The inclusion of actor Finn Wolfhard only makes the comparison that much harder to avoid.
The Honest Trailer points out all the major 80s references in the film, including the movie theater marquee that announces several big films from the period, the movie’s love of all things New Kids on the Block, and the original Street Fighter video game, which most people never played.