Short answers, pulled from the story.
The Duffer Brothers, Matt and Ross, created the television series Stranger Things. They crafted a narrative that felt like a lost 1980s film by drawing from the works of Steven Spielberg, Stephen King, and John Carpenter.
The events of Stranger Things began on the 6th of November 1983 when a small boy named Will Byers walked home from a bike ride and never returned to his mother, Joyce. This disappearance launched a search that uncovered a secret government laboratory and a portal to the Upside Down.
The dimension that exists as a wormhole between Hawkins and another reality is known as the Upside Down. It is a twisted reflection of the other world filled with shadowy creatures and a hive mind that sought to consume humanity.
Michael Stein and Kyle Dixon of the electronic band Survive composed the original score for the series Stranger Things. They used synthesizers to evoke the sounds of Jean-Michel Jarre, Tangerine Dream, and John Carpenter.
The show Stranger Things drew heavily from the MKUltra program to ground its supernatural elements in a historical context that felt plausible to the audience. This program involved experiments with psychic children and the manipulation of the human mind conducted at the Hawkins National Laboratory.