The Duffer brothers didn't want to change the title, despite moving the show to Indiana
Even in the final stages, the Duffers internally referred to the show as Montauk. It wasn't until the absolute last moment that they settled on Stranger Things.
There were alternate titles, but we'll never hear them
The creative staff made a list of alternate 1980s titles before settling on Stranger Things, and that list is still in existence. Unfortunately, Matt Duffer thinks they're terrible, so we'll never see them: "I hope this never, ever comes out on the internet -- the list of alternate titles for the show. I was like: if you leak this, I will kill you. It is so embarrassing."
Eleven was originally a Jean Grey-like badass right from the beginning
In early drafts of the Stranger Things pilot, Eleven used her telekinetic powers to escape the facility. Instead, the Duffer brothers decided to tease out how powerful Eleven actually was and left the escape from the facility to the viewer's imagination.