This is how you do a teaser trailer properly. It doesn't reveal any of the plot and provides way more questions than I had before watching it. It does give enough images to make it clear that the second season of Stranger Things will follow the path of being a deep and meticulously crafted homage to 1980s sci-fi and kids on adventures movies, especially conjuring up memories of Stephen King and Steven Spielberg from the time period. What made the first season work and what the teaser promises too, is that even if it is influenced by pop culture of the time that it twist and manipulates its references into something completely new. There is a scene in the teaser of a boy standing in front of an open door with light pouring out that is a homage to Close Encounters of the Third Kind but then makes it much more sinister with some giant spider-like creature being revealed through flashes of light.
The teaser does reveal the return of Eleven, which I am sure everyone assumed was a formality. Millie Bobby Brown was fantastic in the first season and I loved her chemistry with the boys, so it is good to see she should be a crucial part of the second season story. Based on the flipping of the Netflix logo, it is clear that the Upside Down will continue to be a major part. That dastardly corporations with their hideous experiments is either back at it or there will be some flashbacks. But then again what is a 1980s homage without sinister agents that kids need to avoid?
Speaking of kids, the quick clips of the boys biking and being at school dressed as Ghostbusters only shows three of them. Does that mean poor Will goes missing again? Or is he still suffering from the side effects of too much time spent in the Upside Down? Will he be coughing up more slugs? The teaser doesn't tell you much.
What it does tell me is that Netflix is playing a cruel trick but tantalizing us with a second season, but not delivering until Halloween. I guess it gives lots of time for needless speculation.